3999660 has 96 divisors (see below), whose sum is σ = 13063680. Its totient is φ = 895488.

The previous prime is 3999659. The next prime is 3999661. The reversal of 3999660 is 669993.

3999660 is digitally balanced in base 8, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (3999659) and next prime (3999661).

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

3999660 is strictly pandigital in base 8.

It is not an unprimeable number, because it can be changed into a prime (3999661) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37327 + ... + 37433.

It is an arithmetic number, because the mean of its divisors is an integer number (136080).

Almost surely, 2^3999660 is an apocalyptic number.

3999660 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 3999660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6531840).

3999660 is an abundant number, since it is smaller than the sum of its proper divisors (9064020).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3999660 is a wasteful number, since it uses less digits than its factorization.

3999660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 213 counting only the distinct ones).

The product of its (nonzero) digits is 78732, while the sum is 42.

The square root of 3999660 is about 1999.9149981937. The cubic root of 3999660 is about 158.7356074331.

It can be divided in two parts, 39 and 99660, that added together give a palindrome (99699).

The spelling of 3999660 in words is "three million, nine hundred ninety-nine thousand, six hundred sixty".