21213879860 has 24 divisors (see below), whose sum is σ = 44559352320. Its totient is φ = 8483608224.

The previous prime is 21213879853. The next prime is 21213879919. The reversal of 21213879860 is 6897831212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30320 + ... + 208199.

It is an arithmetic number, because the mean of its divisors is an integer number (1856639680).

Almost surely, 2^21213879860 is an apocalyptic number.

21213879860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21213879860 is an abundant number, since it is smaller than the sum of its proper divisors (23345472460).

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

21213879860 is a wasteful number, since it uses less digits than its factorization.

21213879860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242975 (or 242973 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 47.

The spelling of 21213879860 in words is "twenty-one billion, two hundred thirteen million, eight hundred seventy-nine thousand, eight hundred sixty".