21215250400 has 72 divisors (see below), whose sum is σ = 52373835360. Its totient is φ = 8390722560.

The previous prime is 21215250359. The next prime is 21215250403. The reversal of 21215250400 is 405251212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21215250403) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 77784 + ... + 220183.

It is an arithmetic number, because the mean of its divisors is an integer number (727414380).

Almost surely, 2^21215250400 is an apocalyptic number.

21215250400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21215250400 is an abundant number, since it is smaller than the sum of its proper divisors (31158584960).

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

21215250400 is a wasteful number, since it uses less digits than its factorization.

21215250400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298076 (or 298063 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 22.

The spelling of 21215250400 in words is "twenty-one billion, two hundred fifteen million, two hundred fifty thousand, four hundred".