21870388720 has 40 divisors (see below), whose sum is σ = 50858619840. Its totient is φ = 8746440960.

The previous prime is 21870388711. The next prime is 21870388733. The reversal of 21870388720 is 2788307812.

It is a tau number, because it is divible by the number of its divisors (40).

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, 432946 + ... + 480814.

It is an arithmetic number, because the mean of its divisors is an integer number (1271465496).

Almost surely, 2^21870388720 is an apocalyptic number.

21870388720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21870388720 is an abundant number, since it is smaller than the sum of its proper divisors (28988231120).

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

21870388720 is a wasteful number, since it uses less digits than its factorization.

21870388720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53593 (or 53587 counting only the distinct ones).

The product of its (nonzero) digits is 301056, while the sum is 46.

The spelling of 21870388720 in words is "twenty-one billion, eight hundred seventy million, three hundred eighty-eight thousand, seven hundred twenty".