155199861 has 8 divisors (see below), whose sum is σ = 229925760. Its totient is φ = 103466556.

The previous prime is 155199853. The next prime is 155199881. The reversal of 155199861 is 168991551.

155199861 is a `hidden beast` number, since 1 + 551 + 9 + 98 + 6 + 1 = 666.

It is not a de Polignac number, because 155199861 - 2³ = 155199853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155199841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2874045 + ... + 2874098.

It is an arithmetic number, because the mean of its divisors is an integer number (28740720).

Almost surely, 2^155199861 is an apocalyptic number.

It is an amenable number.

155199861 is a deficient number, since it is larger than the sum of its proper divisors (74725899).

155199861 is an equidigital number, since it uses as much as digits as its factorization.

155199861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5748152 (or 5748146 counting only the distinct ones).

The product of its digits is 97200, while the sum is 45.

The square root of 155199861 is about 12457.9236231404. The cubic root of 155199861 is about 537.3993159888.

The spelling of 155199861 in words is "one hundred fifty-five million, one hundred ninety-nine thousand, eight hundred sixty-one".