661395955 has 16 divisors (see below), whose sum is σ = 874760544. Its totient is φ = 476052480.

The previous prime is 661395919. The next prime is 661395961. The reversal of 661395955 is 559593166.

It is a happy number.

It is not a de Polignac number, because 661395955 - 2⁹ = 661395443 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 661395899 and 661395908.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 56652 + ... + 67321.

It is an arithmetic number, because the mean of its divisors is an integer number (54672534).

Almost surely, 2^661395955 is an apocalyptic number.

661395955 is a deficient number, since it is larger than the sum of its proper divisors (213364589).

661395955 is a wasteful number, since it uses less digits than its factorization.

661395955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124086.

The product of its digits is 1093500, while the sum is 49.

The square root of 661395955 is about 25717.6195438069. The cubic root of 661395955 is about 871.2721754691.

The spelling of 661395955 in words is "six hundred sixty-one million, three hundred ninety-five thousand, nine hundred fifty-five".