21531611083 has 4 divisors (see below), whose sum is σ = 21791028168. Its totient is φ = 21272194000.

The previous prime is 21531611047. The next prime is 21531611111. The reversal of 21531611083 is 38011613512.

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

It is a cyclic number.

It is not a de Polignac number, because 21531611083 - 2⁹ = 21531610571 is a prime.

It is a super-2 number, since 2×21531611083² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21531611383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129708418 + ... + 129708583.

It is an arithmetic number, because the mean of its divisors is an integer number (5447757042).

Almost surely, 2^21531611083 is an apocalyptic number.

21531611083 is a deficient number, since it is larger than the sum of its proper divisors (259417085).

21531611083 is an equidigital number, since it uses as much as digits as its factorization.

21531611083 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259417084.

The product of its (nonzero) digits is 4320, while the sum is 31.

The spelling of 21531611083 in words is "twenty-one billion, five hundred thirty-one million, six hundred eleven thousand, eighty-three".