20644501231 has 2 divisors, whose sum is σ = 20644501232. Its totient is φ = 20644501230.

The previous prime is 20644501219. The next prime is 20644501247. The reversal of 20644501231 is 13210544602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20644501231 - 2¹³ = 20644493039 is a prime.

It is a super-2 number, since 2×20644501231² (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 20644501231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20644541231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10322250615 + 10322250616.

It is an arithmetic number, because the mean of its divisors is an integer number (10322250616).

Almost surely, 2^20644501231 is an apocalyptic number.

20644501231 is a deficient number, since it is larger than the sum of its proper divisors (1).

20644501231 is an equidigital number, since it uses as much as digits as its factorization.

20644501231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5760, while the sum is 28.

The spelling of 20644501231 in words is "twenty billion, six hundred forty-four million, five hundred one thousand, two hundred thirty-one".