661184462621 has 2 divisors, whose sum is σ = 661184462622. Its totient is φ = 661184462620.

The previous prime is 661184462551. The next prime is 661184462623. The reversal of 661184462621 is 126264481166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 579751279396 + 81433183225 = 761414^2 + 285365^2 .

It is a cyclic number.

It is not a de Polignac number, because 661184462621 - 2¹⁸ = 661184200477 is a prime.

It is a super-2 number, since 2×661184462621² (a number of 24 digits) contains 22 as substring.

Together with 661184462623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661184462623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330592231310 + 330592231311.

It is an arithmetic number, because the mean of its divisors is an integer number (330592231311).

Almost surely, 2^661184462621 is an apocalyptic number.

It is an amenable number.

661184462621 is a deficient number, since it is larger than the sum of its proper divisors (1).

661184462621 is an equidigital number, since it uses as much as digits as its factorization.

661184462621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 663552, while the sum is 47.

The spelling of 661184462621 in words is "six hundred sixty-one billion, one hundred eighty-four million, four hundred sixty-two thousand, six hundred twenty-one".