21257197200 has 480 divisors, whose sum is σ = 79515446400. Its totient is φ = 5386106880.

The previous prime is 21257197187. The next prime is 21257197219. The reversal of 21257197200 is 279175212.

21257197200 is a `hidden beast` number, since 2 + 12 + 571 + 9 + 72 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 20983894 + ... + 20984906.

It is an arithmetic number, because the mean of its divisors is an integer number (165657180).

Almost surely, 2^21257197200 is an apocalyptic number.

21257197200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21257197200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39757723200).

21257197200 is an abundant number, since it is smaller than the sum of its proper divisors (58258249200).

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

21257197200 is a wasteful number, since it uses less digits than its factorization.

21257197200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1136 (or 1119 counting only the distinct ones).

The product of its (nonzero) digits is 17640, while the sum is 36.

The spelling of 21257197200 in words is "twenty-one billion, two hundred fifty-seven million, one hundred ninety-seven thousand, two hundred".