20845520651 has 2 divisors, whose sum is σ = 20845520652. Its totient is φ = 20845520650.

The previous prime is 20845520623. The next prime is 20845520671. The reversal of 20845520651 is 15602554802.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20845520651 is a prime.

It is a super-2 number, since 2×20845520651² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (20845520611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10422760325 + 10422760326.

It is an arithmetic number, because the mean of its divisors is an integer number (10422760326).

Almost surely, 2^20845520651 is an apocalyptic number.

20845520651 is a deficient number, since it is larger than the sum of its proper divisors (1).

20845520651 is an equidigital number, since it uses as much as digits as its factorization.

20845520651 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96000, while the sum is 38.

The spelling of 20845520651 in words is "twenty billion, eight hundred forty-five million, five hundred twenty thousand, six hundred fifty-one".