51654247621 has 2 divisors, whose sum is σ = 51654247622. Its totient is φ = 51654247620.

The previous prime is 51654247607. The next prime is 51654247693. The reversal of 51654247621 is 12674245615.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 43051685121 + 8602562500 = 207489^2 + 92750^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51654247621 is a prime.

It is a super-2 number, since 2×51654247621² (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 (51654247321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25827123810 + 25827123811.

It is an arithmetic number, because the mean of its divisors is an integer number (25827123811).

Almost surely, 2^51654247621 is an apocalyptic number.

It is an amenable number.

51654247621 is a deficient number, since it is larger than the sum of its proper divisors (1).

51654247621 is an equidigital number, since it uses as much as digits as its factorization.

51654247621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 403200, while the sum is 43.

The spelling of 51654247621 in words is "fifty-one billion, six hundred fifty-four million, two hundred forty-seven thousand, six hundred twenty-one".