18861497 has 4 divisors (see below), whose sum is σ = 18887760. Its totient is φ = 18835236.

The previous prime is 18861461. The next prime is 18861499. The reversal of 18861497 is 79416881.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 79416881 = 353 ⋅224977.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18861497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18861499) 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, 12023 + ... + 13500.

It is an arithmetic number, because the mean of its divisors is an integer number (4721940).

Almost surely, 2^18861497 is an apocalyptic number.

It is an amenable number.

18861497 is a deficient number, since it is larger than the sum of its proper divisors (26263).

18861497 is an equidigital number, since it uses as much as digits as its factorization.

18861497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26262.

The product of its digits is 96768, while the sum is 44.

The square root of 18861497 is about 4342.9825005404. The cubic root of 18861497 is about 266.1901941245.

The spelling of 18861497 in words is "eighteen million, eight hundred sixty-one thousand, four hundred ninety-seven".