20890644331 has 2 divisors, whose sum is σ = 20890644332. Its totient is φ = 20890644330.

The previous prime is 20890644311. The next prime is 20890644373. The reversal of 20890644331 is 13344609802.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20890644331 is a prime.

It is a super-2 number, since 2×20890644331² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20890644301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10445322165 + 10445322166.

It is an arithmetic number, because the mean of its divisors is an integer number (10445322166).

Almost surely, 2^20890644331 is an apocalyptic number.

20890644331 is a deficient number, since it is larger than the sum of its proper divisors (1).

20890644331 is an equidigital number, since it uses as much as digits as its factorization.

20890644331 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 124416, while the sum is 40.

The spelling of 20890644331 in words is "twenty billion, eight hundred ninety million, six hundred forty-four thousand, three hundred thirty-one".