155015591 has 4 divisors (see below), whose sum is σ = 155067192. Its totient is φ = 154963992.

The previous prime is 155015587. The next prime is 155015647. The reversal of 155015591 is 195510551.

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 155015591 - 2² = 155015587 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155015521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20996 + ... + 27401.

It is an arithmetic number, because the mean of its divisors is an integer number (38766798).

Almost surely, 2^155015591 is an apocalyptic number.

155015591 is a deficient number, since it is larger than the sum of its proper divisors (51601).

155015591 is an equidigital number, since it uses as much as digits as its factorization.

155015591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51600.

The product of its (nonzero) digits is 5625, while the sum is 32.

The square root of 155015591 is about 12450.5257318717. The cubic root of 155015591 is about 537.1865456318.

The spelling of 155015591 in words is "one hundred fifty-five million, fifteen thousand, five hundred ninety-one".