191661155 has 16 divisors (see below), whose sum is σ = 263839680. Its totient is φ = 130929792.

The previous prime is 191661149. The next prime is 191661157. The reversal of 191661155 is 551166191.

It is not a de Polignac number, because 191661155 - 2¹⁸ = 191399011 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is not an unprimeable number, because it can be changed into a prime (191661157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 764 + ... + 19593.

It is an arithmetic number, because the mean of its divisors is an integer number (16489980).

Almost surely, 2^191661155 is an apocalyptic number.

191661155 is a deficient number, since it is larger than the sum of its proper divisors (72178525).

191661155 is a wasteful number, since it uses less digits than its factorization.

191661155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20638.

The product of its digits is 8100, while the sum is 35.

The square root of 191661155 is about 13844.1740454243. The cubic root of 191661155 is about 576.5602539382.

The spelling of 191661155 in words is "one hundred ninety-one million, six hundred sixty-one thousand, one hundred fifty-five".