20172715878 has 32 divisors (see below), whose sum is σ = 46186099200. Its totient is φ = 5754003840.

The previous prime is 20172715877. The next prime is 20172715883. The reversal of 20172715878 is 87851727102.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20172715877) 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, 375763 + ... + 426078.

It is an arithmetic number, because the mean of its divisors is an integer number (1443315600).

Almost surely, 2^20172715878 is an apocalyptic number.

20172715878 is an abundant number, since it is smaller than the sum of its proper divisors (26013383322).

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

20172715878 is a wasteful number, since it uses less digits than its factorization.

20172715878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 802452.

The product of its (nonzero) digits is 439040, while the sum is 48.

The spelling of 20172715878 in words is "twenty billion, one hundred seventy-two million, seven hundred fifteen thousand, eight hundred seventy-eight".