39724220978 has 54 divisors (see below), whose sum is σ = 66540557349. Its totient is φ = 17777852352.

The previous prime is 39724220971. The next prime is 39724220983. The reversal of 39724220978 is 87902242793.

It can be written as a sum of positive squares in 14 ways, for example, as 13248700609 + 26475520369 = 115103^2 + 162713^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=140933.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39724220971) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 135577400 + ... + 135577692.

Almost surely, 2^39724220978 is an apocalyptic number.

39724220978 is a deficient number, since it is larger than the sum of its proper divisors (26816336371).

39724220978 is an equidigital number, since it uses as much as digits as its factorization.

39724220978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 688 (or 345 counting only the distinct ones).

The product of its (nonzero) digits is 3048192, while the sum is 53.

The spelling of 39724220978 in words is "thirty-nine billion, seven hundred twenty-four million, two hundred twenty thousand, nine hundred seventy-eight".