3990861840 has 480 divisors, whose sum is σ = 15480616320. Its totient is φ = 845365248.

The previous prime is 3990861839. The next prime is 3990861871. The reversal of 3990861840 is 481680993.

It is a hoax number, since the sum of its digits (48) 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 (48).

It is a self number, because there is not a number n which added to its sum of digits gives 3990861840.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 11842152 + ... + 11842488.

It is an arithmetic number, because the mean of its divisors is an integer number (32251284).

Almost surely, 2^3990861840 is an apocalyptic number.

3990861840 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 3990861840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7740308160).

3990861840 is an abundant number, since it is smaller than the sum of its proper divisors (11489754480).

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

3990861840 is a wasteful number, since it uses less digits than its factorization.

3990861840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 439 (or 426 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 48.

The square root of 3990861840 is about 63173.2683973213. The cubic root of 3990861840 is about 1586.1913031937.

The spelling of 3990861840 in words is "three billion, nine hundred ninety million, eight hundred sixty-one thousand, eight hundred forty".