20431267640 has 128 divisors (see below), whose sum is σ = 53169177600. Its totient is φ = 6921323520.

The previous prime is 20431267627. The next prime is 20431267693. The reversal of 20431267640 is 4676213402.

It is a super-2 number, since 2×20431267640² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 20431267640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8368820 + ... + 8371260.

It is an arithmetic number, because the mean of its divisors is an integer number (415384200).

Almost surely, 2^20431267640 is an apocalyptic number.

20431267640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20431267640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26584588800).

20431267640 is an abundant number, since it is smaller than the sum of its proper divisors (32737909960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20431267640 is a wasteful number, since it uses less digits than its factorization.

20431267640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2805 (or 2801 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 35.

The spelling of 20431267640 in words is "twenty billion, four hundred thirty-one million, two hundred sixty-seven thousand, six hundred forty".