421645005261 has 96 divisors (see below), whose sum is σ = 649927875168. Its totient is φ = 263055237120.

The previous prime is 421645005253. The next prime is 421645005319. The reversal of 421645005261 is 162500546124.

421645005261 is a `hidden beast` number, since 4 + 2 + 1 + 645 + 0 + 0 + 5 + 2 + 6 + 1 = 666.

It can be written as a sum of positive squares in 16 ways, for example, as 4837898025 + 416807107236 = 69555^2 + 645606^2 .

It is not a de Polignac number, because 421645005261 - 2³ = 421645005253 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421645005161) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 492000745 + ... + 492001601.

It is an arithmetic number, because the mean of its divisors is an integer number (6770082033).

Almost surely, 2^421645005261 is an apocalyptic number.

It is an amenable number.

421645005261 is a deficient number, since it is larger than the sum of its proper divisors (228282869907).

421645005261 is a wasteful number, since it uses less digits than its factorization.

421645005261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1471 (or 1468 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The spelling of 421645005261 in words is "four hundred twenty-one billion, six hundred forty-five million, five thousand, two hundred sixty-one".