155149991 has 16 divisors (see below), whose sum is σ = 169814400. Its totient is φ = 141235488.

The previous prime is 155149987. The next prime is 155149997. The reversal of 155149991 is 199941551.

It is a cyclic number.

It is not a de Polignac number, because 155149991 - 2² = 155149987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155149997) 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 15 ways as a sum of consecutive naturals, for example, 57020 + ... + 59678.

It is an arithmetic number, because the mean of its divisors is an integer number (10613400).

Almost surely, 2^155149991 is an apocalyptic number.

155149991 is a deficient number, since it is larger than the sum of its proper divisors (14664409).

155149991 is a wasteful number, since it uses less digits than its factorization.

155149991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2798.

The product of its digits is 72900, while the sum is 44.

The square root of 155149991 is about 12455.9219249319. The cubic root of 155149991 is about 537.3417494103.

The spelling of 155149991 in words is "one hundred fifty-five million, one hundred forty-nine thousand, nine hundred ninety-one".