51640547257 has 4 divisors (see below), whose sum is σ = 55612897060. Its totient is φ = 47668197456.

The previous prime is 51640547251. The next prime is 51640547291. The reversal of 51640547257 is 75274504615.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 22623468921 + 29017078336 = 150411^2 + 170344^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51640547257 is a prime.

It is a super-2 number, since 2×51640547257² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51640547251) 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, 1986174882 + ... + 1986174907.

It is an arithmetic number, because the mean of its divisors is an integer number (13903224265).

Almost surely, 2^51640547257 is an apocalyptic number.

It is an amenable number.

51640547257 is a deficient number, since it is larger than the sum of its proper divisors (3972349803).

51640547257 is a wasteful number, since it uses less digits than its factorization.

51640547257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3972349802.

The product of its (nonzero) digits is 1176000, while the sum is 46.

The spelling of 51640547257 in words is "fifty-one billion, six hundred forty million, five hundred forty-seven thousand, two hundred fifty-seven".