155655991 has 8 divisors (see below), whose sum is σ = 162713600. Its totient is φ = 148725720.

The previous prime is 155655989. The next prime is 155656027. The reversal of 155655991 is 199556551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 155655991 - 2¹ = 155655989 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 (155655971) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29331 + ... + 34228.

It is an arithmetic number, because the mean of its divisors is an integer number (20339200).

Almost surely, 2^155655991 is an apocalyptic number.

155655991 is a deficient number, since it is larger than the sum of its proper divisors (7057609).

155655991 is an equidigital number, since it uses as much as digits as its factorization.

155655991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63669.

The product of its digits is 303750, while the sum is 46.

The square root of 155655991 is about 12476.2170147846. The cubic root of 155655991 is about 537.9252705037.

The spelling of 155655991 in words is "one hundred fifty-five million, six hundred fifty-five thousand, nine hundred ninety-one".