18420919 has 6 divisors (see below), whose sum is σ = 20247920. Its totient is φ = 16746180.

The previous prime is 18420917. The next prime is 18420923. The reversal of 18420919 is 91902481.

It is not a de Polignac number, because 18420919 - 2¹ = 18420917 is a prime.

It is a super-2 number, since 2×18420919² = 678660513609122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18420917) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 75999 + ... + 76240.

Almost surely, 2^18420919 is an apocalyptic number.

18420919 is a deficient number, since it is larger than the sum of its proper divisors (1827001).

18420919 is a wasteful number, since it uses less digits than its factorization.

18420919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152261 (or 152250 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 18420919 is about 4291.9598087587. The cubic root of 18420919 is about 264.1012343235.

The spelling of 18420919 in words is "eighteen million, four hundred twenty thousand, nine hundred nineteen".