39664640 has 88 divisors (see below), whose sum is σ = 97469952. Its totient is φ = 15482880.

The previous prime is 39664631. The next prime is 39664643. The reversal of 39664640 is 4646693.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 39664594 and 39664603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39664643) 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, 312257 + ... + 312383.

Almost surely, 2^39664640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 39664640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48734976).

39664640 is an abundant number, since it is smaller than the sum of its proper divisors (57805312).

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

39664640 is a wasteful number, since it uses less digits than its factorization.

39664640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213 (or 195 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 38.

The square root of 39664640 is about 6297.9869799802. The cubic root of 39664640 is about 341.0367432307.

It can be divided in two parts, 39664 and 640, that added together give a palindrome (40304).

The spelling of 39664640 in words is "thirty-nine million, six hundred sixty-four thousand, six hundred forty".