21211514531 has 4 divisors (see below), whose sum is σ = 21211806000. Its totient is φ = 21211223064.

The previous prime is 21211514507. The next prime is 21211514537. The reversal of 21211514531 is 13541511212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21211514531 - 2²² = 21207320227 is a prime.

It is a super-2 number, since 2×21211514531² (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 21211514531.

It is not an unprimeable number, because it can be changed into a prime (21211514537) 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, 65090 + ... + 216008.

It is an arithmetic number, because the mean of its divisors is an integer number (5302951500).

Almost surely, 2^21211514531 is an apocalyptic number.

21211514531 is a deficient number, since it is larger than the sum of its proper divisors (291469).

21211514531 is a wasteful number, since it uses less digits than its factorization.

21211514531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291468.

The product of its digits is 1200, while the sum is 26.

The spelling of 21211514531 in words is "twenty-one billion, two hundred eleven million, five hundred fourteen thousand, five hundred thirty-one".