21170590477 has 4 divisors (see below), whose sum is σ = 21742768636. Its totient is φ = 20598412320.

The previous prime is 21170590429. The next prime is 21170590481. The reversal of 21170590477 is 77409507112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10134247561 + 11036342916 = 100669^2 + 105054^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21170590477 is a prime.

It is a super-2 number, since 2×21170590477² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21170597477) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 286089024 + ... + 286089097.

It is an arithmetic number, because the mean of its divisors is an integer number (5435692159).

Almost surely, 2^21170590477 is an apocalyptic number.

It is an amenable number.

21170590477 is a deficient number, since it is larger than the sum of its proper divisors (572178159).

21170590477 is an equidigital number, since it uses as much as digits as its factorization.

21170590477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 572178158.

The product of its (nonzero) digits is 123480, while the sum is 43.

The spelling of 21170590477 in words is "twenty-one billion, one hundred seventy million, five hundred ninety thousand, four hundred seventy-seven".