18722906 has 4 divisors (see below), whose sum is σ = 28084362. Its totient is φ = 9361452.

The previous prime is 18722903. The next prime is 18722909. The reversal of 18722906 is 60922781.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (18722903) and next prime (18722909).

It can be written as a sum of positive squares in only one way, i.e., 17147881 + 1575025 = 4141^2 + 1255^2 .

It is not an unprimeable number, because it can be changed into a prime (18722903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4680725 + ... + 4680728.

Almost surely, 2^18722906 is an apocalyptic number.

18722906 is a deficient number, since it is larger than the sum of its proper divisors (9361456).

18722906 is an equidigital number, since it uses as much as digits as its factorization.

18722906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9361455.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 18722906 is about 4326.9973422687. The cubic root of 18722906 is about 265.5366176266.

The spelling of 18722906 in words is "eighteen million, seven hundred twenty-two thousand, nine hundred six".