21521205310 has 32 divisors (see below), whose sum is σ = 42582443904. Its totient is φ = 7766148000.

The previous prime is 21521205253. The next prime is 21521205371. The reversal of 21521205310 is 1350212512.

It is a super-2 number, since 2×21521205310² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (22).

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, 732336 + ... + 761155.

It is an arithmetic number, because the mean of its divisors is an integer number (1330701372).

Almost surely, 2^21521205310 is an apocalyptic number.

21521205310 is a deficient number, since it is larger than the sum of its proper divisors (21061238594).

21521205310 is a wasteful number, since it uses less digits than its factorization.

21521205310 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1493640.

The product of its (nonzero) digits is 600, while the sum is 22.

Adding to 21521205310 its reverse (1350212512), we get a palindrome (22871417822).

The spelling of 21521205310 in words is "twenty-one billion, five hundred twenty-one million, two hundred five thousand, three hundred ten".