21400520320 has 32 divisors (see below), whose sum is σ = 51160620420. Its totient is φ = 8560207872.

The previous prime is 21400520303. The next prime is 21400520327. The reversal of 21400520320 is 2302500412.

It can be written as a sum of positive squares in 2 ways, for example, as 20729088576 + 671431744 = 143976^2 + 25912^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (21400520327) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16718517 + ... + 16719796.

Almost surely, 2^21400520320 is an apocalyptic number.

21400520320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21400520320 is an abundant number, since it is smaller than the sum of its proper divisors (29760100100).

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

21400520320 is an equidigital number, since it uses as much as digits as its factorization.

21400520320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33438332 (or 33438320 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The spelling of 21400520320 in words is "twenty-one billion, four hundred million, five hundred twenty thousand, three hundred twenty".