18122420 has 12 divisors (see below), whose sum is σ = 38057124. Its totient is φ = 7248960.

The previous prime is 18122399. The next prime is 18122431. The reversal of 18122420 is 2422181.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 3083536 + 15038884 = 1756^2 + 3878^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 906121 = 18122420 / (1 + 8 + 1 + 2 + 2 + 4 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 18122392 and 18122401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 453041 + ... + 453080.

It is an arithmetic number, because the mean of its divisors is an integer number (3171427).

Almost surely, 2^18122420 is an apocalyptic number.

18122420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18122420 is an abundant number, since it is smaller than the sum of its proper divisors (19934704).

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

18122420 is a wasteful number, since it uses less digits than its factorization.

18122420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 906130 (or 906128 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 18122420 is about 4257.0435750647. The cubic root of 18122420 is about 262.6669293489. Note that the first 3 decimals are identical.

The spelling of 18122420 in words is "eighteen million, one hundred twenty-two thousand, four hundred twenty".