661161663 has 8 divisors (see below), whose sum is σ = 979498800. Its totient is φ = 440774424.

The previous prime is 661161661. The next prime is 661161719. The reversal of 661161663 is 366161166.

It is a happy number.

It is not a de Polignac number, because 661161663 - 2¹ = 661161661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661161661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12243708 + ... + 12243761.

It is an arithmetic number, because the mean of its divisors is an integer number (122437350).

Almost surely, 2^661161663 is an apocalyptic number.

661161663 is a deficient number, since it is larger than the sum of its proper divisors (318337137).

661161663 is a wasteful number, since it uses less digits than its factorization.

661161663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24487478 (or 24487472 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 661161663 is about 25713.0640531229. The cubic root of 661161663 is about 871.1692838968.

The spelling of 661161663 in words is "six hundred sixty-one million, one hundred sixty-one thousand, six hundred sixty-three".