20009172457 has 2 divisors, whose sum is σ = 20009172458. Its totient is φ = 20009172456.

The previous prime is 20009172451. The next prime is 20009172467. The reversal of 20009172457 is 75427190002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19909492201 + 99680256 = 141101^2 + 9984^2 .

It is a cyclic number.

It is not a de Polignac number, because 20009172457 - 2¹¹ = 20009170409 is a prime.

It is not a weakly prime, because it can be changed into another prime (20009172451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10004586228 + 10004586229.

It is an arithmetic number, because the mean of its divisors is an integer number (10004586229).

Almost surely, 2^20009172457 is an apocalyptic number.

It is an amenable number.

20009172457 is a deficient number, since it is larger than the sum of its proper divisors (1).

20009172457 is an equidigital number, since it uses as much as digits as its factorization.

20009172457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 35280, while the sum is 37.

The spelling of 20009172457 in words is "twenty billion, nine million, one hundred seventy-two thousand, four hundred fifty-seven".