51561650064521 has 4 divisors (see below), whose sum is σ = 51562227364500. Its totient is φ = 51561072764544.

The previous prime is 51561650064517. The next prime is 51561650064553. The reversal of 51561650064521 is 12546005616515.

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 45195434790025 + 6366215274496 = 6722755^2 + 2523136^2 .

It is a cyclic number.

It is not a de Polignac number, because 51561650064521 - 2² = 51561650064517 is a prime.

It is a super-2 number, since 2×51561650064521² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51567650064521) 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, 288515996 + ... + 288694653.

It is an arithmetic number, because the mean of its divisors is an integer number (12890556841125).

Almost surely, 2^{51561650064521} is an apocalyptic number.

It is an amenable number.

51561650064521 is a deficient number, since it is larger than the sum of its proper divisors (577299979).

51561650064521 is an equidigital number, since it uses as much as digits as its factorization.

51561650064521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 577299978.

The product of its (nonzero) digits is 1080000, while the sum is 47.

The spelling of 51561650064521 in words is "fifty-one trillion, five hundred sixty-one billion, six hundred fifty million, sixty-four thousand, five hundred twenty-one".