20157020509 has 2 divisors, whose sum is σ = 20157020510. Its totient is φ = 20157020508.

The previous prime is 20157020503. The next prime is 20157020591. The reversal of 20157020509 is 90502075102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17826255225 + 2330765284 = 133515^2 + 48278^2 .

It is a cyclic number.

It is not a de Polignac number, because 20157020509 - 2³ = 20157020501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20157020501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10078510254 + 10078510255.

It is an arithmetic number, because the mean of its divisors is an integer number (10078510255).

Almost surely, 2^20157020509 is an apocalyptic number.

It is an amenable number.

20157020509 is a deficient number, since it is larger than the sum of its proper divisors (1).

20157020509 is an equidigital number, since it uses as much as digits as its factorization.

20157020509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6300, while the sum is 31.

The spelling of 20157020509 in words is "twenty billion, one hundred fifty-seven million, twenty thousand, five hundred nine".