21309213504 has 112 divisors (see below), whose sum is σ = 58766090240. Its totient is φ = 6807006720.

The previous prime is 21309213491. The next prime is 21309213511. The reversal of 21309213504 is 40531290312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 595677 + ... + 630435.

Almost surely, 2^21309213504 is an apocalyptic number.

21309213504 is a gapful number since it is divisible by the number (24) 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 21309213504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29383045120).

21309213504 is an abundant number, since it is smaller than the sum of its proper divisors (37456876736).

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

21309213504 is a wasteful number, since it uses less digits than its factorization.

21309213504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34908 (or 34898 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 30.

The spelling of 21309213504 in words is "twenty-one billion, three hundred nine million, two hundred thirteen thousand, five hundred four".