18856997 has 4 divisors (see below), whose sum is σ = 18869676. Its totient is φ = 18844320.

The previous prime is 18856979. The next prime is 18857009. The reversal of 18856997 is 79965881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79965881 = 3313 ⋅24137.

It can be written as a sum of positive squares in 2 ways, for example, as 12859396 + 5997601 = 3586^2 + 2449^2 .

It is a cyclic number.

It is not a de Polignac number, because 18856997 - 2¹² = 18852901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18556997) 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, 3758 + ... + 7199.

It is an arithmetic number, because the mean of its divisors is an integer number (4717419).

Almost surely, 2^18856997 is an apocalyptic number.

It is an amenable number.

18856997 is a deficient number, since it is larger than the sum of its proper divisors (12679).

18856997 is a wasteful number, since it uses less digits than its factorization.

18856997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12678.

The product of its digits is 1088640, while the sum is 53.

The square root of 18856997 is about 4342.4643924850. The cubic root of 18856997 is about 266.1690231088.

The spelling of 18856997 in words is "eighteen million, eight hundred fifty-six thousand, nine hundred ninety-seven".