21307515400 has 24 divisors (see below), whose sum is σ = 49539973770. Its totient is φ = 8523006080.

The previous prime is 21307515373. The next prime is 21307515409. The reversal of 21307515400 is 451570312.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 19980953316 + 1326562084 = 141354^2 + 36422^2 .

It is not an unprimeable number, because it can be changed into a prime (21307515409) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 53268589 + ... + 53268988.

Almost surely, 2^21307515400 is an apocalyptic number.

21307515400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21307515400 is an abundant number, since it is smaller than the sum of its proper divisors (28232458370).

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

21307515400 is a wasteful number, since it uses less digits than its factorization.

21307515400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106537593 (or 106537584 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 28.

The spelling of 21307515400 in words is "twenty-one billion, three hundred seven million, five hundred fifteen thousand, four hundred".