78658816638 has 64 divisors (see below), whose sum is σ = 171436849920. Its totient is φ = 23966587392.

The previous prime is 78658816637. The next prime is 78658816651. The reversal of 78658816638 is 83661885687.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78658816633) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 420756 + ... + 578232.

It is an arithmetic number, because the mean of its divisors is an integer number (2678700780).

Almost surely, 2^78658816638 is an apocalyptic number.

78658816638 is an abundant number, since it is smaller than the sum of its proper divisors (92778033282).

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

78658816638 is a wasteful number, since it uses less digits than its factorization.

78658816638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157641.

The product of its digits is 92897280, while the sum is 66.

The spelling of 78658816638 in words is "seventy-eight billion, six hundred fifty-eight million, eight hundred sixteen thousand, six hundred thirty-eight".