15978020437 has 4 divisors (see below), whose sum is σ = 15979145260. Its totient is φ = 15976895616.

The previous prime is 15978020413. The next prime is 15978020441. The reversal of 15978020437 is 73402087951.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6155030116 + 9822990321 = 78454^2 + 99111^2 .

It is a cyclic number.

It is not a de Polignac number, because 15978020437 - 2⁷ = 15978020309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15978020447) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 540828 + ... + 569605.

It is an arithmetic number, because the mean of its divisors is an integer number (3994786315).

Almost surely, 2^15978020437 is an apocalyptic number.

It is an amenable number.

15978020437 is a deficient number, since it is larger than the sum of its proper divisors (1124823).

15978020437 is a wasteful number, since it uses less digits than its factorization.

15978020437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1124822.

The product of its (nonzero) digits is 423360, while the sum is 46.

The spelling of 15978020437 in words is "fifteen billion, nine hundred seventy-eight million, twenty thousand, four hundred thirty-seven".