21851701029 has 12 divisors (see below), whose sum is σ = 31565476332. Its totient is φ = 14566920000.

The previous prime is 21851701019. The next prime is 21851701049. The reversal of 21851701029 is 92010715812.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 2745550404 + 19106150625 = 52398^2 + 138225^2 .

It is not a de Polignac number, because 21851701029 - 2²⁷ = 21717483301 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21851700984 and 21851701002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21851701019) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 107119 + ... + 234899.

It is an arithmetic number, because the mean of its divisors is an integer number (2630456361).

Almost surely, 2^21851701029 is an apocalyptic number.

It is an amenable number.

21851701029 is a deficient number, since it is larger than the sum of its proper divisors (9713775303).

21851701029 is a wasteful number, since it uses less digits than its factorization.

21851701029 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146788 (or 146785 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 36.

The spelling of 21851701029 in words is "twenty-one billion, eight hundred fifty-one million, seven hundred one thousand, twenty-nine".