155979591 has 4 divisors (see below), whose sum is σ = 207972792. Its totient is φ = 103986392.

The previous prime is 155979587. The next prime is 155979613. The reversal of 155979591 is 195979551.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 155979591 - 2² = 155979587 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155979521) 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 3 ways as a sum of consecutive naturals, for example, 25996596 + ... + 25996601.

It is an arithmetic number, because the mean of its divisors is an integer number (51993198).

Almost surely, 2^155979591 is an apocalyptic number.

155979591 is a deficient number, since it is larger than the sum of its proper divisors (51993201).

155979591 is an equidigital number, since it uses as much as digits as its factorization.

155979591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51993200.

The product of its digits is 637875, while the sum is 51.

The square root of 155979591 is about 12489.1789562004. The cubic root of 155979591 is about 538.2977845468.

The spelling of 155979591 in words is "one hundred fifty-five million, nine hundred seventy-nine thousand, five hundred ninety-one".