21055000031 has 16 divisors (see below), whose sum is σ = 22907233440. Its totient is φ = 19351500480.

The previous prime is 21054999997. The next prime is 21055000033. The reversal of 21055000031 is 13000055012.

It is not a de Polignac number, because 21055000031 - 2³⁰ = 19981258207 is a prime.

It is a super-2 number, since 2×21055000031² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21054999973 and 21055000009.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21055000033) 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, 491336 + ... + 532466.

It is an arithmetic number, because the mean of its divisors is an integer number (1431702090).

Almost surely, 2^21055000031 is an apocalyptic number.

21055000031 is a deficient number, since it is larger than the sum of its proper divisors (1852233409).

21055000031 is an equidigital number, since it uses as much as digits as its factorization.

21055000031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41403 (or 41377 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 17.

Adding to 21055000031 its reverse (13000055012), we get a palindrome (34055055043).

The spelling of 21055000031 in words is "twenty-one billion, fifty-five million, thirty-one", and thus it is an aban number and an uban number.