20623435621 has 2 divisors, whose sum is σ = 20623435622. Its totient is φ = 20623435620.

The previous prime is 20623435603. The next prime is 20623435633. The reversal of 20623435621 is 12653432602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17079614721 + 3543820900 = 130689^2 + 59530^2 .

It is a cyclic number.

It is not a de Polignac number, because 20623435621 - 2⁹ = 20623435109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20623439621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10311717810 + 10311717811.

It is an arithmetic number, because the mean of its divisors is an integer number (10311717811).

Almost surely, 2^20623435621 is an apocalyptic number.

It is an amenable number.

20623435621 is a deficient number, since it is larger than the sum of its proper divisors (1).

20623435621 is an equidigital number, since it uses as much as digits as its factorization.

20623435621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 34.

The spelling of 20623435621 in words is "twenty billion, six hundred twenty-three million, four hundred thirty-five thousand, six hundred twenty-one".