18910639 has 8 divisors (see below), whose sum is σ = 21341520. Its totient is φ = 16598400.

The previous prime is 18910609. The next prime is 18910649. The reversal of 18910639 is 93601981.

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 18910639 - 2¹⁹ = 18386351 is a prime.

It is a super-2 number, since 2×18910639² = 715224534776642, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18910598 and 18910607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18910609) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29322 + ... + 29959.

It is an arithmetic number, because the mean of its divisors is an integer number (2667690).

Almost surely, 2^18910639 is an apocalyptic number.

18910639 is a deficient number, since it is larger than the sum of its proper divisors (2430881).

18910639 is a wasteful number, since it uses less digits than its factorization.

18910639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59321.

The product of its (nonzero) digits is 11664, while the sum is 37.

The square root of 18910639 is about 4348.6364529586. The cubic root of 18910639 is about 266.4211721563.

The spelling of 18910639 in words is "eighteen million, nine hundred ten thousand, six hundred thirty-nine".