20856434431 has 12 divisors (see below), whose sum is σ = 25316418672. Its totient is φ = 17099684448.

The previous prime is 20856434419. The next prime is 20856434441. The reversal of 20856434431 is 13443465802.

It is not a de Polignac number, because 20856434431 - 2²¹ = 20854337279 is a prime.

It is a super-2 number, since 2×20856434431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20856434441) 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, 9251950 + ... + 9254203.

It is an arithmetic number, because the mean of its divisors is an integer number (2109701556).

Almost surely, 2^20856434431 is an apocalyptic number.

20856434431 is a deficient number, since it is larger than the sum of its proper divisors (4459984241).

20856434431 is a wasteful number, since it uses less digits than its factorization.

20856434431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18506190 (or 18506183 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 40.

The spelling of 20856434431 in words is "twenty billion, eight hundred fifty-six million, four hundred thirty-four thousand, four hundred thirty-one".