18990497 has 4 divisors (see below), whose sum is σ = 19118100. Its totient is φ = 18862896.

The previous prime is 18990493. The next prime is 18990523. The reversal of 18990497 is 79409981.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12645136 + 6345361 = 3556^2 + 2519^2 .

It is a cyclic number.

It is not a de Polignac number, because 18990497 - 2² = 18990493 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18990493) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63578 + ... + 63875.

It is an arithmetic number, because the mean of its divisors is an integer number (4779525).

Almost surely, 2^18990497 is an apocalyptic number.

It is an amenable number.

18990497 is a deficient number, since it is larger than the sum of its proper divisors (127603).

18990497 is a wasteful number, since it uses less digits than its factorization.

18990497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127602.

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 18990497 is about 4357.8087383455. The cubic root of 18990497 is about 266.7956700482.

The spelling of 18990497 in words is "eighteen million, nine hundred ninety thousand, four hundred ninety-seven".