3997640 has 32 divisors (see below), whose sum is σ = 9072000. Its totient is φ = 1585344.

The previous prime is 3997639. The next prime is 3997649. The reversal of 3997640 is 467993.

It is a super-2 number, since 2×3997640² = 31962251139200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 3997594 and 3997603.

It is not an unprimeable number, because it can be changed into a prime (3997649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5201 + ... + 5919.

It is an arithmetic number, because the mean of its divisors is an integer number (283500).

Almost surely, 2^3997640 is an apocalyptic number.

It is an amenable number.

3997640 is an abundant number, since it is smaller than the sum of its proper divisors (5074360).

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

3997640 is a wasteful number, since it uses less digits than its factorization.

3997640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 869 (or 865 counting only the distinct ones).

The product of its (nonzero) digits is 40824, while the sum is 38.

The square root of 3997640 is about 1999.4099129493. The cubic root of 3997640 is about 158.7088801677.

It can be divided in two parts, 39 and 97640, that added together give a palindrome (97679).

The spelling of 3997640 in words is "three million, nine hundred ninety-seven thousand, six hundred forty".