18978129 has 12 divisors (see below), whose sum is σ = 27504516. Its totient is φ = 12609792.

The previous prime is 18978119. The next prime is 18978161. The reversal of 18978129 is 92187981.

It can be written as a sum of positive squares in 2 ways, for example, as 3415104 + 15563025 = 1848^2 + 3945^2 .

It is not a de Polignac number, because 18978129 - 2⁵ = 18978097 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18978109) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 552 + ... + 6185.

It is an arithmetic number, because the mean of its divisors is an integer number (2292043).

Almost surely, 2^18978129 is an apocalyptic number.

It is an amenable number.

18978129 is a deficient number, since it is larger than the sum of its proper divisors (8526387).

18978129 is a wasteful number, since it uses less digits than its factorization.

18978129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7056 (or 7053 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 18978129 is about 4356.3894454009. The cubic root of 18978129 is about 266.7377385216.

The spelling of 18978129 in words is "eighteen million, nine hundred seventy-eight thousand, one hundred twenty-nine".