20643642431 has 8 divisors (see below), whose sum is σ = 21436699680. Its totient is φ = 19855999072.

The previous prime is 20643642421. The next prime is 20643642451. The reversal of 20643642431 is 13424634602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20643642431 - 2²⁶ = 20576533567 is a prime.

It is a super-2 number, since 2×20643642431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20643642391 and 20643642400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20643642421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1345700 + ... + 1360953.

It is an arithmetic number, because the mean of its divisors is an integer number (2679587460).

Almost surely, 2^20643642431 is an apocalyptic number.

20643642431 is a deficient number, since it is larger than the sum of its proper divisors (793057249).

20643642431 is a wasteful number, since it uses less digits than its factorization.

20643642431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2706945.

The product of its (nonzero) digits is 82944, while the sum is 35.

The spelling of 20643642431 in words is "twenty billion, six hundred forty-three million, six hundred forty-two thousand, four hundred thirty-one".