18906643 has 8 divisors (see below), whose sum is σ = 22067712. Its totient is φ = 15860616.

The previous prime is 18906599. The next prime is 18906659. The reversal of 18906643 is 34660981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18906643 - 2⁹ = 18906131 is a prime.

It is a super-2 number, since 2×18906643² = 714922299058898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18906443) 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, 28405 + ... + 29062.

It is an arithmetic number, because the mean of its divisors is an integer number (2758464).

Almost surely, 2^18906643 is an apocalyptic number.

18906643 is a deficient number, since it is larger than the sum of its proper divisors (3161069).

18906643 is an equidigital number, since it uses as much as digits as its factorization.

18906643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57521.

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 18906643 is about 4348.1769743192. The cubic root of 18906643 is about 266.4024050485.

The spelling of 18906643 in words is "eighteen million, nine hundred six thousand, six hundred forty-three".