20420633641 has 2 divisors, whose sum is σ = 20420633642. Its totient is φ = 20420633640.

The previous prime is 20420633621. The next prime is 20420633669. The reversal of 20420633641 is 14633602402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19478389225 + 942244416 = 139565^2 + 30696^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20420633641 is a prime.

It is not a weakly prime, because it can be changed into another prime (20420633621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210316820 + 10210316821.

It is an arithmetic number, because the mean of its divisors is an integer number (10210316821).

Almost surely, 2^20420633641 is an apocalyptic number.

It is an amenable number.

20420633641 is a deficient number, since it is larger than the sum of its proper divisors (1).

20420633641 is an equidigital number, since it uses as much as digits as its factorization.

20420633641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 31.

The spelling of 20420633641 in words is "twenty billion, four hundred twenty million, six hundred thirty-three thousand, six hundred forty-one".