39921440 has 96 divisors (see below), whose sum is σ = 107639280. Its totient is φ = 13860864.

The previous prime is 39921433. The next prime is 39921443. The reversal of 39921440 is 4412993.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 6697744 + 33223696 = 2588^2 + 5764^2 .

It is a hoax number, since the sum of its digits (32) 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 (32).

It is a junction number, because it is equal to n+sod(n) for n = 39921397 and 39921406.

It is not an unprimeable number, because it can be changed into a prime (39921443) 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, 34796 + ... + 35924.

Almost surely, 2^39921440 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 39921440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53819640).

39921440 is an abundant number, since it is smaller than the sum of its proper divisors (67717840).

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

39921440 is a wasteful number, since it uses less digits than its factorization.

39921440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1174 (or 1166 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 39921440 is about 6318.3415545537. The cubic root of 39921440 is about 341.7711497494.

The spelling of 39921440 in words is "thirty-nine million, nine hundred twenty-one thousand, four hundred forty".