18961655 has 4 divisors (see below), whose sum is σ = 22753992. Its totient is φ = 15169320.

The previous prime is 18961643. The next prime is 18961661. The reversal of 18961655 is 55616981.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 18961655 - 2¹⁸ = 18699511 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1896161 + ... + 1896170.

It is an arithmetic number, because the mean of its divisors is an integer number (5688498).

Almost surely, 2^18961655 is an apocalyptic number.

18961655 is a deficient number, since it is larger than the sum of its proper divisors (3792337).

18961655 is an equidigital number, since it uses as much as digits as its factorization.

18961655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3792336.

The product of its digits is 64800, while the sum is 41.

The square root of 18961655 is about 4354.4982489375. The cubic root of 18961655 is about 266.6605354493.

The spelling of 18961655 in words is "eighteen million, nine hundred sixty-one thousand, six hundred fifty-five".