18866420 has 12 divisors (see below), whose sum is σ = 39619524. Its totient is φ = 7546560.

The previous prime is 18866401. The next prime is 18866423. The reversal of 18866420 is 2466881.

It can be written as a sum of positive squares in 2 ways, for example, as 7279204 + 11587216 = 2698^2 + 3404^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18866423) 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, 471641 + ... + 471680.

It is an arithmetic number, because the mean of its divisors is an integer number (3301627).

Almost surely, 2^18866420 is an apocalyptic number.

18866420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18866420 is an abundant number, since it is smaller than the sum of its proper divisors (20753104).

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

18866420 is a wasteful number, since it uses less digits than its factorization.

18866420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 943330 (or 943328 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 35.

The square root of 18866420 is about 4343.5492399649. The cubic root of 18866420 is about 266.2133513591.

The spelling of 18866420 in words is "eighteen million, eight hundred sixty-six thousand, four hundred twenty".