661614513551 has 2 divisors, whose sum is σ = 661614513552. Its totient is φ = 661614513550.

The previous prime is 661614513457. The next prime is 661614513563. The reversal of 661614513551 is 155315416166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661614513551 - 2¹⁰ = 661614512527 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661614513251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330807256775 + 330807256776.

It is an arithmetic number, because the mean of its divisors is an integer number (330807256776).

Almost surely, 2^661614513551 is an apocalyptic number.

661614513551 is a deficient number, since it is larger than the sum of its proper divisors (1).

661614513551 is an equidigital number, since it uses as much as digits as its factorization.

661614513551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 324000, while the sum is 44.

The spelling of 661614513551 in words is "six hundred sixty-one billion, six hundred fourteen million, five hundred thirteen thousand, five hundred fifty-one".