21111534431 has 16 divisors (see below), whose sum is σ = 23292872064. Its totient is φ = 19010938464.

The previous prime is 21111534421. The next prime is 21111534461. The reversal of 21111534431 is 13443511112.

It is a de Polignac number, because none of the positive numbers 2^k-21111534431 is a prime.

It is a super-2 number, since 2×21111534431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21111534431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111534421) 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, 439460 + ... + 485126.

It is an arithmetic number, because the mean of its divisors is an integer number (1455804504).

Almost surely, 2^21111534431 is an apocalyptic number.

21111534431 is a deficient number, since it is larger than the sum of its proper divisors (2181337633).

21111534431 is a wasteful number, since it uses less digits than its factorization.

21111534431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46550.

The product of its digits is 1440, while the sum is 26.

The spelling of 21111534431 in words is "twenty-one billion, one hundred eleven million, five hundred thirty-four thousand, four hundred thirty-one".