51661111651 has 2 divisors, whose sum is σ = 51661111652. Its totient is φ = 51661111650.

The previous prime is 51661111639. The next prime is 51661111669. The reversal of 51661111651 is 15611116615.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51661111651 - 2²⁷ = 51526893923 is a prime.

It is not a weakly prime, because it can be changed into another prime (51661111751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25830555825 + 25830555826.

It is an arithmetic number, because the mean of its divisors is an integer number (25830555826).

Almost surely, 2^51661111651 is an apocalyptic number.

51661111651 is a deficient number, since it is larger than the sum of its proper divisors (1).

51661111651 is an equidigital number, since it uses as much as digits as its factorization.

51661111651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5400, while the sum is 34.

The spelling of 51661111651 in words is "fifty-one billion, six hundred sixty-one million, one hundred eleven thousand, six hundred fifty-one".