51720521113 has 2 divisors, whose sum is σ = 51720521114. Its totient is φ = 51720521112.

The previous prime is 51720521033. The next prime is 51720521119. The reversal of 51720521113 is 31112502715.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29067863049 + 22652658064 = 170493^2 + 150508^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51720521113 is a prime.

It is not a weakly prime, because it can be changed into another prime (51720521119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25860260556 + 25860260557.

It is an arithmetic number, because the mean of its divisors is an integer number (25860260557).

Almost surely, 2^51720521113 is an apocalyptic number.

It is an amenable number.

51720521113 is a deficient number, since it is larger than the sum of its proper divisors (1).

51720521113 is an equidigital number, since it uses as much as digits as its factorization.

51720521113 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2100, while the sum is 28.

The spelling of 51720521113 in words is "fifty-one billion, seven hundred twenty million, five hundred twenty-one thousand, one hundred thirteen".