20651515457 has 2 divisors, whose sum is σ = 20651515458. Its totient is φ = 20651515456.

The previous prime is 20651515447. The next prime is 20651515481. The reversal of 20651515457 is 75451515602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20243313841 + 408201616 = 142279^2 + 20204^2 .

It is a cyclic number.

It is not a de Polignac number, because 20651515457 - 2⁶ = 20651515393 is a prime.

It is not a weakly prime, because it can be changed into another prime (20651515447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10325757728 + 10325757729.

It is an arithmetic number, because the mean of its divisors is an integer number (10325757729).

Almost surely, 2^20651515457 is an apocalyptic number.

It is an amenable number.

20651515457 is a deficient number, since it is larger than the sum of its proper divisors (1).

20651515457 is an equidigital number, since it uses as much as digits as its factorization.

20651515457 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 210000, while the sum is 41.

The spelling of 20651515457 in words is "twenty billion, six hundred fifty-one million, five hundred fifteen thousand, four hundred fifty-seven".