18242820 has 60 divisors (see below), whose sum is σ = 57233484. Its totient is φ = 4864320.

The previous prime is 18242803. The next prime is 18242837. The reversal of 18242820 is 2824281.

It is an interprime number because it is at equal distance from previous prime (18242803) and next prime (18242837).

It can be written as a sum of positive squares in 2 ways, for example, as 13883076 + 4359744 = 3726^2 + 2088^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4011 + ... + 7250.

Almost surely, 2^18242820 is an apocalyptic number.

18242820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18242820 is an abundant number, since it is smaller than the sum of its proper divisors (38990664).

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

18242820 is a wasteful number, since it uses less digits than its factorization.

18242820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11282 (or 11271 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 18242820 is about 4271.1614345515. The cubic root of 18242820 is about 263.2473396863.

The spelling of 18242820 in words is "eighteen million, two hundred forty-two thousand, eight hundred twenty".