21220812575 has 24 divisors (see below), whose sum is σ = 28200019488. Its totient is φ = 15799639680.

The previous prime is 21220812559. The next prime is 21220812593. The reversal of 21220812575 is 57521802212.

It is not a de Polignac number, because 21220812575 - 2⁴ = 21220812559 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 477452 + ... + 520001.

It is an arithmetic number, because the mean of its divisors is an integer number (1175000812).

Almost surely, 2^21220812575 is an apocalyptic number.

21220812575 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21220812575 is a deficient number, since it is larger than the sum of its proper divisors (6979206913).

21220812575 is a wasteful number, since it uses less digits than its factorization.

21220812575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 997523 (or 997518 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 35.

The spelling of 21220812575 in words is "twenty-one billion, two hundred twenty million, eight hundred twelve thousand, five hundred seventy-five".