155661115 has 4 divisors (see below), whose sum is σ = 186793344. Its totient is φ = 124528888.

The previous prime is 155661101. The next prime is 155661127. The reversal of 155661115 is 511166551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 511166551 = 7 ⋅73023793.

It is a cyclic number.

It is not a de Polignac number, because 155661115 - 2¹⁹ = 155136827 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15566107 + ... + 15566116.

It is an arithmetic number, because the mean of its divisors is an integer number (46698336).

Almost surely, 2^155661115 is an apocalyptic number.

155661115 is a deficient number, since it is larger than the sum of its proper divisors (31132229).

155661115 is an equidigital number, since it uses as much as digits as its factorization.

155661115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31132228.

The product of its digits is 4500, while the sum is 31.

The square root of 155661115 is about 12476.4223638029. The cubic root of 155661115 is about 537.9311730474.

The spelling of 155661115 in words is "one hundred fifty-five million, six hundred sixty-one thousand, one hundred fifteen".