51721725457 has 2 divisors, whose sum is σ = 51721725458. Its totient is φ = 51721725456.

The previous prime is 51721725397. The next prime is 51721725481. The reversal of 51721725457 is 75452712715.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42336766081 + 9384959376 = 205759^2 + 96876^2 .

It is a cyclic number.

It is not a de Polignac number, because 51721725457 - 2¹⁵ = 51721692689 is a prime.

It is not a weakly prime, because it can be changed into another prime (51721722457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25860862728 + 25860862729.

It is an arithmetic number, because the mean of its divisors is an integer number (25860862729).

Almost surely, 2^51721725457 is an apocalyptic number.

It is an amenable number.

51721725457 is a deficient number, since it is larger than the sum of its proper divisors (1).

51721725457 is an equidigital number, since it uses as much as digits as its factorization.

51721725457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 686000, while the sum is 46.

The spelling of 51721725457 in words is "fifty-one billion, seven hundred twenty-one million, seven hundred twenty-five thousand, four hundred fifty-seven".