155981998 has 24 divisors (see below), whose sum is σ = 245863800. Its totient is φ = 74211984.

The previous prime is 155981993. The next prime is 155982007. The reversal of 155981998 is 899189551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155981993) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 400788 + ... + 401176.

It is an arithmetic number, because the mean of its divisors is an integer number (10244325).

Almost surely, 2^155981998 is an apocalyptic number.

155981998 is a deficient number, since it is larger than the sum of its proper divisors (89881802).

155981998 is a wasteful number, since it uses less digits than its factorization.

155981998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816 (or 793 counting only the distinct ones).

The product of its digits is 1166400, while the sum is 55.

The square root of 155981998 is about 12489.2753192489. The cubic root of 155981998 is about 538.3005534478.

The spelling of 155981998 in words is "one hundred fifty-five million, nine hundred eighty-one thousand, nine hundred ninety-eight".