21878712423 has 6 divisors (see below), whose sum is σ = 31602584624. Its totient is φ = 14585808276.

The previous prime is 21878712421. The next prime is 21878712467. The reversal of 21878712423 is 32421787812.

21878712423 is a `hidden beast` number, since 218 + 7 + 8 + 7 + 1 + 2 + 423 = 666.

It is not a de Polignac number, because 21878712423 - 2¹ = 21878712421 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 (21878712421) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1215484015 + ... + 1215484032.

Almost surely, 2^21878712423 is an apocalyptic number.

21878712423 is a deficient number, since it is larger than the sum of its proper divisors (9723872201).

21878712423 is a wasteful number, since it uses less digits than its factorization.

21878712423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2430968053 (or 2430968050 counting only the distinct ones).

The product of its digits is 301056, while the sum is 45.

The spelling of 21878712423 in words is "twenty-one billion, eight hundred seventy-eight million, seven hundred twelve thousand, four hundred twenty-three".