20644831 has 2 divisors, whose sum is σ = 20644832. Its totient is φ = 20644830.

The previous prime is 20644807. The next prime is 20644837. The reversal of 20644831 is 13844602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20644831 - 2⁹ = 20644319 is a prime.

It is a super-2 number, since 2×20644831² = 852418094037122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20644831.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20644837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10322415 + 10322416.

It is an arithmetic number, because the mean of its divisors is an integer number (10322416).

Almost surely, 2^20644831 is an apocalyptic number.

20644831 is a deficient number, since it is larger than the sum of its proper divisors (1).

20644831 is an equidigital number, since it uses as much as digits as its factorization.

20644831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 20644831 is about 4543.6583278235. The cubic root of 20644831 is about 274.3281937685.

The spelling of 20644831 in words is "twenty million, six hundred forty-four thousand, eight hundred thirty-one".