20861308878 has 16 divisors (see below), whose sum is σ = 41725472976. Its totient is φ = 6953293760.

The previous prime is 20861308877. The next prime is 20861308961. The reversal of 20861308878 is 87880316802.

It is a self number, because there is not a number n which added to its sum of digits gives 20861308878.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20861308877) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17301 + ... + 204992.

It is an arithmetic number, because the mean of its divisors is an integer number (2607842061).

Almost surely, 2^20861308878 is an apocalyptic number.

20861308878 is an abundant number, since it is smaller than the sum of its proper divisors (20864164098).

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

20861308878 is a wasteful number, since it uses less digits than its factorization.

20861308878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237939.

The product of its (nonzero) digits is 1032192, while the sum is 51.

The spelling of 20861308878 in words is "twenty billion, eight hundred sixty-one million, three hundred eight thousand, eight hundred seventy-eight".