18978669 has 12 divisors (see below), whose sum is σ = 28155036. Its totient is φ = 12310272.

The previous prime is 18978667. The next prime is 18978683. The reversal of 18978669 is 96687981.

It can be written as a sum of positive squares in 2 ways, for example, as 16305444 + 2673225 = 4038^2 + 1635^2 .

It is not a de Polignac number, because 18978669 - 2¹ = 18978667 is a prime.

It is a super-2 number, since 2×18978669² = 720379754023122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18978667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 28164 + ... + 28829.

It is an arithmetic number, because the mean of its divisors is an integer number (2346253).

Almost surely, 2^18978669 is an apocalyptic number.

It is an amenable number.

18978669 is a deficient number, since it is larger than the sum of its proper divisors (9176367).

18978669 is a wasteful number, since it uses less digits than its factorization.

18978669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57036 (or 57033 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 54.

The square root of 18978669 is about 4356.4514228900. The cubic root of 18978669 is about 266.7402683989.

The spelling of 18978669 in words is "eighteen million, nine hundred seventy-eight thousand, six hundred sixty-nine".