21851701019 has 2 divisors, whose sum is σ = 21851701020. Its totient is φ = 21851701018.

The previous prime is 21851700973. The next prime is 21851701049. The reversal of 21851701019 is 91010715812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21851701019 - 2²⁰ = 21850652443 is a prime.

It is a super-2 number, since 2×21851701019² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21851701019.

It is not a weakly prime, because it can be changed into another prime (21851701049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10925850509 + 10925850510.

It is an arithmetic number, because the mean of its divisors is an integer number (10925850510).

Almost surely, 2^21851701019 is an apocalyptic number.

21851701019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21851701019 is an equidigital number, since it uses as much as digits as its factorization.

21851701019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 35.

The spelling of 21851701019 in words is "twenty-one billion, eight hundred fifty-one million, seven hundred one thousand, nineteen".