21497257200 has 120 divisors (see below), whose sum is σ = 69389058816. Its totient is φ = 5688800000.

The previous prime is 21497257183. The next prime is 21497257207. The reversal of 21497257200 is 275279412.

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21497257207) 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, 88825 + ... + 225575.

Almost surely, 2^21497257200 is an apocalyptic number.

21497257200 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 21497257200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34694529408).

21497257200 is an abundant number, since it is smaller than the sum of its proper divisors (47891801616).

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

21497257200 is a wasteful number, since it uses less digits than its factorization.

21497257200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136903 (or 136892 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 39.

The spelling of 21497257200 in words is "twenty-one billion, four hundred ninety-seven million, two hundred fifty-seven thousand, two hundred".