661116637 has 2 divisors, whose sum is σ = 661116638. Its totient is φ = 661116636.

The previous prime is 661116611. The next prime is 661116641. The reversal of 661116637 is 736611166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 517380516 + 143736121 = 22746^2 + 11989^2 .

It is a cyclic number.

It is not a de Polignac number, because 661116637 - 2¹⁵ = 661083869 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661116596 and 661116605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661116667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330558318 + 330558319.

It is an arithmetic number, because the mean of its divisors is an integer number (330558319).

Almost surely, 2^661116637 is an apocalyptic number.

It is an amenable number.

661116637 is a deficient number, since it is larger than the sum of its proper divisors (1).

661116637 is an equidigital number, since it uses as much as digits as its factorization.

661116637 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 37.

The square root of 661116637 is about 25712.1884910639. The cubic root of 661116637 is about 871.1495075139.

The spelling of 661116637 in words is "six hundred sixty-one million, one hundred sixteen thousand, six hundred thirty-seven".