21530105707731 has 16 divisors (see below), whose sum is σ = 29114491737600. Its totient is φ = 14149608448640.

The previous prime is 21530105707711. The next prime is 21530105707769. The reversal of 21530105707731 is 13770750103512.

It is not a de Polignac number, because 21530105707731 - 2⁴³ = 12734012685523 is a prime.

It is a super-2 number, since 2×21530105707731² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21530105707711) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3988806 + ... + 7679243.

It is an arithmetic number, because the mean of its divisors is an integer number (1819655733600).

Almost surely, 2^{21530105707731} is an apocalyptic number.

21530105707731 is a deficient number, since it is larger than the sum of its proper divisors (7584386029869).

21530105707731 is a wasteful number, since it uses less digits than its factorization.

21530105707731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11676786.

The product of its (nonzero) digits is 154350, while the sum is 42.

The spelling of 21530105707731 in words is "twenty-one trillion, five hundred thirty billion, one hundred five million, seven hundred seven thousand, seven hundred thirty-one".