21661226435025 has 18 divisors (see below), whose sum is σ = 38797663348470. Its totient is φ = 11552654098560.

The previous prime is 21661226435003. The next prime is 21661226435027. The reversal of 21661226435025 is 52053462216612.

21661226435025 is a `hidden beast` number, since 2 + 1 + 6 + 6 + 12 + 264 + 350 + 25 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 485473104081 + 21175753330944 = 696759^2 + 4601712^2 .

It is not a de Polignac number, because 21661226435025 - 2⁶ = 21661226434961 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (21661226435027) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 48136058520 + ... + 48136058969.

Almost surely, 2^{21661226435025} is an apocalyptic number.

21661226435025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21661226435025 is a deficient number, since it is larger than the sum of its proper divisors (17136436913445).

21661226435025 is a wasteful number, since it uses less digits than its factorization.

21661226435025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96272117505 (or 96272117497 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 45.

The spelling of 21661226435025 in words is "twenty-one trillion, six hundred sixty-one billion, two hundred twenty-six million, four hundred thirty-five thousand, twenty-five".