3921720 has 64 divisors (see below), whose sum is σ = 12839040. Its totient is φ = 950400.

The previous prime is 3921719. The next prime is 3921721. The reversal of 3921720 is 271293.

It is an interprime number because it is at equal distance from previous prime (3921719) and next prime (3921721).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3921721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 166 + ... + 2805.

It is an arithmetic number, because the mean of its divisors is an integer number (200610).

Almost surely, 2^3921720 is an apocalyptic number.

3921720 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 3921720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6419520).

3921720 is an abundant number, since it is smaller than the sum of its proper divisors (8917320).

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

3921720 is a wasteful number, since it uses less digits than its factorization.

3921720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2996 (or 2992 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 24.

The square root of 3921720 is about 1980.3333052797. Note that the first 4 decimals coincide. The cubic root of 3921720 is about 157.6977611561.

It can be divided in two parts, 392 and 1720, that added together give a palindrome (2112).

The spelling of 3921720 in words is "three million, nine hundred twenty-one thousand, seven hundred twenty".