51318586021 has 2 divisors, whose sum is σ = 51318586022. Its totient is φ = 51318586020.

The previous prime is 51318585959. The next prime is 51318586157. The reversal of 51318586021 is 12068581315.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47737880100 + 3580705921 = 218490^2 + 59839^2 .

It is a cyclic number.

It is not a de Polignac number, because 51318586021 - 2²³ = 51310197413 is a prime.

It is a super-2 number, since 2×51318586021² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51318586421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25659293010 + 25659293011.

It is an arithmetic number, because the mean of its divisors is an integer number (25659293011).

Almost surely, 2^51318586021 is an apocalyptic number.

It is an amenable number.

51318586021 is a deficient number, since it is larger than the sum of its proper divisors (1).

51318586021 is an equidigital number, since it uses as much as digits as its factorization.

51318586021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 57600, while the sum is 40.

The spelling of 51318586021 in words is "fifty-one billion, three hundred eighteen million, five hundred eighty-six thousand, twenty-one".