51690890471989 has 2 divisors, whose sum is σ = 51690890471990. Its totient is φ = 51690890471988.

The previous prime is 51690890471977. The next prime is 51690890472019. The reversal of 51690890471989 is 98917409809615.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49367247549489 + 2323642922500 = 7026183^2 + 1524350^2 .

It is a cyclic number.

It is not a de Polignac number, because 51690890471989 - 2¹⁹ = 51690889947701 is a prime.

It is a super-2 number, since 2×51690890471989² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51690890471939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25845445235994 + 25845445235995.

It is an arithmetic number, because the mean of its divisors is an integer number (25845445235995).

Almost surely, 2^{51690890471989} is an apocalyptic number.

It is an amenable number.

51690890471989 is a deficient number, since it is larger than the sum of its proper divisors (1).

51690890471989 is an equidigital number, since it uses as much as digits as its factorization.

51690890471989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 352719360, while the sum is 76.

The spelling of 51690890471989 in words is "fifty-one trillion, six hundred ninety billion, eight hundred ninety million, four hundred seventy-one thousand, nine hundred eighty-nine".