21235526564 has 24 divisors (see below), whose sum is σ = 42475805568. Its totient is φ = 9099921600.

The previous prime is 21235526563. The next prime is 21235526581. The reversal of 21235526564 is 46562553212.

It is a Smith number, since the sum of its digits (41) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21235526563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 246872 + ... + 321584.

It is an arithmetic number, because the mean of its divisors is an integer number (1769825232).

Almost surely, 2^21235526564 is an apocalyptic number.

It is an amenable number.

21235526564 is an abundant number, since it is smaller than the sum of its proper divisors (21240279004).

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

21235526564 is a wasteful number, since it uses less digits than its factorization.

21235526564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84875 (or 84873 counting only the distinct ones).

The product of its digits is 432000, while the sum is 41.

The spelling of 21235526564 in words is "twenty-one billion, two hundred thirty-five million, five hundred twenty-six thousand, five hundred sixty-four".