18401388 has 24 divisors (see below), whose sum is σ = 43748208. Its totient is φ = 6017856.

The previous prime is 18401381. The next prime is 18401389. The reversal of 18401388 is 88310481.

It is a happy number.

It is a super-2 number, since 2×18401388² = 677222160653088, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18401381) 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, 13831 + ... + 15102.

It is an arithmetic number, because the mean of its divisors is an integer number (1822842).

Almost surely, 2^18401388 is an apocalyptic number.

It is an amenable number.

18401388 is an abundant number, since it is smaller than the sum of its proper divisors (25346820).

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

18401388 is a wasteful number, since it uses less digits than its factorization.

18401388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28993 (or 28991 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 33.

The square root of 18401388 is about 4289.6839044386. The cubic root of 18401388 is about 264.0078624839.

The spelling of 18401388 in words is "eighteen million, four hundred one thousand, three hundred eighty-eight".