661012155 has 12 divisors (see below), whose sum is σ = 1145754480. Its totient is φ = 352539792.

The previous prime is 661012133. The next prime is 661012169. The reversal of 661012155 is 551210166.

It is a happy number.

It is not a de Polignac number, because 661012155 - 2⁶ = 661012091 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7344535 + ... + 7344624.

It is an arithmetic number, because the mean of its divisors is an integer number (95479540).

Almost surely, 2^661012155 is an apocalyptic number.

661012155 is a deficient number, since it is larger than the sum of its proper divisors (484742325).

661012155 is a wasteful number, since it uses less digits than its factorization.

661012155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14689170 (or 14689167 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 661012155 is about 25710.1566506313. The cubic root of 661012155 is about 871.1036133237.

The spelling of 661012155 in words is "six hundred sixty-one million, twelve thousand, one hundred fifty-five".