155861889 has 4 divisors (see below), whose sum is σ = 207815856. Its totient is φ = 103907924.

The previous prime is 155861879. The next prime is 155861891. The reversal of 155861889 is 988168551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 155861889 - 2²⁵ = 122307457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (155861879) 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, 25976979 + ... + 25976984.

It is an arithmetic number, because the mean of its divisors is an integer number (51953964).

Almost surely, 2^155861889 is an apocalyptic number.

It is an amenable number.

155861889 is a deficient number, since it is larger than the sum of its proper divisors (51953967).

155861889 is an equidigital number, since it uses as much as digits as its factorization.

155861889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51953966.

The product of its digits is 691200, while the sum is 51.

The square root of 155861889 is about 12484.4659076790. The cubic root of 155861889 is about 538.1623508684.

The spelling of 155861889 in words is "one hundred fifty-five million, eight hundred sixty-one thousand, eight hundred eighty-nine".