20456751557 has 4 divisors (see below), whose sum is σ = 22316456256. Its totient is φ = 18597046860.

The previous prime is 20456751533. The next prime is 20456751589. The reversal of 20456751557 is 75515765402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20456751557 - 2¹⁰ = 20456750533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20456751857) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 929852333 + ... + 929852354.

It is an arithmetic number, because the mean of its divisors is an integer number (5579114064).

Almost surely, 2^20456751557 is an apocalyptic number.

It is an amenable number.

20456751557 is a deficient number, since it is larger than the sum of its proper divisors (1859704699).

20456751557 is a wasteful number, since it uses less digits than its factorization.

20456751557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1859704698.

The product of its (nonzero) digits is 1470000, while the sum is 47.

The spelling of 20456751557 in words is "twenty billion, four hundred fifty-six million, seven hundred fifty-one thousand, five hundred fifty-seven".