155817881 has 2 divisors, whose sum is σ = 155817882. Its totient is φ = 155817880.

The previous prime is 155817877. The next prime is 155817887. The reversal of 155817881 is 188718551.

155817881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121992025 + 33825856 = 11045^2 + 5816^2 .

It is a cyclic number.

It is not a de Polignac number, because 155817881 - 2² = 155817877 is a prime.

It is a super-2 number, since 2×155817881² = 48558424078660322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (155817887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77908940 + 77908941.

It is an arithmetic number, because the mean of its divisors is an integer number (77908941).

Almost surely, 2^155817881 is an apocalyptic number.

It is an amenable number.

155817881 is a deficient number, since it is larger than the sum of its proper divisors (1).

155817881 is an equidigital number, since it uses as much as digits as its factorization.

155817881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 89600, while the sum is 44.

The square root of 155817881 is about 12482.7032729293. The cubic root of 155817881 is about 538.1116955986. Note that the first 3 decimals are identical.

The spelling of 155817881 in words is "one hundred fifty-five million, eight hundred seventeen thousand, eight hundred eighty-one".