21878897913 has 24 divisors (see below), whose sum is σ = 33072032448. Its totient is φ = 13911508512.

The previous prime is 21878897899. The next prime is 21878897921. The reversal of 21878897913 is 31979887812.

It is not a de Polignac number, because 21878897913 - 2⁹ = 21878897401 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21878897923) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 80470 + ... + 224127.

It is an arithmetic number, because the mean of its divisors is an integer number (1378001352).

Almost surely, 2^21878897913 is an apocalyptic number.

21878897913 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21878897913 is a deficient number, since it is larger than the sum of its proper divisors (11193134535).

21878897913 is a wasteful number, since it uses less digits than its factorization.

21878897913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304973 (or 304970 counting only the distinct ones).

The product of its digits is 12192768, while the sum is 63.

The spelling of 21878897913 in words is "twenty-one billion, eight hundred seventy-eight million, eight hundred ninety-seven thousand, nine hundred thirteen".