51497979781 has 2 divisors, whose sum is σ = 51497979782. Its totient is φ = 51497979780.

The previous prime is 51497979749. The next prime is 51497979833. The reversal of 51497979781 is 18797979415.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39097152900 + 12400826881 = 197730^2 + 111359^2 .

It is a cyclic number.

It is not a de Polignac number, because 51497979781 - 2⁵ = 51497979749 is a prime.

It is a super-2 number, since 2×51497979781² (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 (51497979581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25748989890 + 25748989891.

It is an arithmetic number, because the mean of its divisors is an integer number (25748989891).

Almost surely, 2^51497979781 is an apocalyptic number.

It is an amenable number.

51497979781 is a deficient number, since it is larger than the sum of its proper divisors (1).

51497979781 is an equidigital number, since it uses as much as digits as its factorization.

51497979781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40007520, while the sum is 67.

The spelling of 51497979781 in words is "fifty-one billion, four hundred ninety-seven million, nine hundred seventy-nine thousand, seven hundred eighty-one".