661117655115 has 24 divisors (see below), whose sum is σ = 1165359939120. Its totient is φ = 346619876544.

The previous prime is 661117655069. The next prime is 661117655129. The reversal of 661117655115 is 511556711166.

661117655115 is a `hidden beast` number, since 6 + 6 + 1 + 11 + 76 + 551 + 15 = 666.

It is not a de Polignac number, because 661117655115 - 2¹³ = 661117646923 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

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 in 23 ways as a sum of consecutive naturals, for example, 124501612 + ... + 124506921.

It is an arithmetic number, because the mean of its divisors is an integer number (48556664130).

Almost surely, 2^661117655115 is an apocalyptic number.

661117655115 is a deficient number, since it is larger than the sum of its proper divisors (504242284005).

661117655115 is a wasteful number, since it uses less digits than its factorization.

661117655115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249008603 (or 249008600 counting only the distinct ones).

The product of its digits is 189000, while the sum is 45.

The spelling of 661117655115 in words is "six hundred sixty-one billion, one hundred seventeen million, six hundred fifty-five thousand, one hundred fifteen".