18661420 has 24 divisors (see below), whose sum is σ = 41252400. Its totient is φ = 7071552.

The previous prime is 18661417. The next prime is 18661429. The reversal of 18661420 is 2416681.

It is not an unprimeable number, because it can be changed into a prime (18661429) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24175 + ... + 24934.

It is an arithmetic number, because the mean of its divisors is an integer number (1718850).

Almost surely, 2^18661420 is an apocalyptic number.

18661420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18661420 is an abundant number, since it is smaller than the sum of its proper divisors (22590980).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18661420 is a wasteful number, since it uses less digits than its factorization.

18661420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49137 (or 49135 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 18661420 is about 4319.8865725850. The cubic root of 18661420 is about 265.2456248799.

The spelling of 18661420 in words is "eighteen million, six hundred sixty-one thousand, four hundred twenty".