21131541305 has 12 divisors (see below), whose sum is σ = 29497906980. Its totient is φ = 14490199584.

The previous prime is 21131541293. The next prime is 21131541323. The reversal of 21131541305 is 50314513112.

It can be written as a sum of positive squares in 2 ways, for example, as 9587543056 + 11543998249 = 97916^2 + 107443^2 .

It is not a de Polignac number, because 21131541305 - 2⁶ = 21131541241 is a prime.

It is a super-2 number, since 2×21131541305² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43125350 + ... + 43125839.

It is an arithmetic number, because the mean of its divisors is an integer number (2458158915).

Almost surely, 2^21131541305 is an apocalyptic number.

It is an amenable number.

21131541305 is a deficient number, since it is larger than the sum of its proper divisors (8366365675).

21131541305 is an equidigital number, since it uses as much as digits as its factorization.

21131541305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86251208 (or 86251201 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 26.

The spelling of 21131541305 in words is "twenty-one billion, one hundred thirty-one million, five hundred forty-one thousand, three hundred five".