18978477 has 16 divisors (see below), whose sum is σ = 30621312. Its totient is φ = 10206720.

The previous prime is 18978469. The next prime is 18978481. The reversal of 18978477 is 77487981.

It is not a de Polignac number, because 18978477 - 2³ = 18978469 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18978457) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26224 + ... + 26937.

It is an arithmetic number, because the mean of its divisors is an integer number (1913832).

Almost surely, 2^18978477 is an apocalyptic number.

18978477 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

18978477 is a deficient number, since it is larger than the sum of its proper divisors (11642835).

18978477 is a wasteful number, since it uses less digits than its factorization.

18978477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53188.

The product of its digits is 790272, while the sum is 51.

The square root of 18978477 is about 4356.4293865504. The cubic root of 18978477 is about 266.7393688924.

The spelling of 18978477 in words is "eighteen million, nine hundred seventy-eight thousand, four hundred seventy-seven".