20917355225 has 48 divisors (see below), whose sum is σ = 28899327408. Its totient is φ = 14918307840.

The previous prime is 20917355167. The next prime is 20917355233. The reversal of 20917355225 is 52255371902.

It can be written as a sum of positive squares in 24 ways, for example, as 14990818969 + 5926536256 = 122437^2 + 76984^2 .

It is not a de Polignac number, because 20917355225 - 2¹² = 20917351129 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1641077 + ... + 1653773.

It is an arithmetic number, because the mean of its divisors is an integer number (602069321).

Almost surely, 2^20917355225 is an apocalyptic number.

20917355225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20917355225 is a deficient number, since it is larger than the sum of its proper divisors (7981972183).

20917355225 is a wasteful number, since it uses less digits than its factorization.

20917355225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12894 (or 12889 counting only the distinct ones).

The product of its (nonzero) digits is 189000, while the sum is 41.

The spelling of 20917355225 in words is "twenty billion, nine hundred seventeen million, three hundred fifty-five thousand, two hundred twenty-five".