18397780 has 24 divisors (see below), whose sum is σ = 39104352. Its totient is φ = 7269792.

The previous prime is 18397777. The next prime is 18397781. The reversal of 18397780 is 8779381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18397781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3882 + ... + 7201.

It is an arithmetic number, because the mean of its divisors is an integer number (1629348).

Almost surely, 2^18397780 is an apocalyptic number.

18397780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18397780 is an abundant number, since it is smaller than the sum of its proper divisors (20706572).

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

18397780 is a wasteful number, since it uses less digits than its factorization.

18397780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11175 (or 11173 counting only the distinct ones).

The product of its (nonzero) digits is 84672, while the sum is 43.

The square root of 18397780 is about 4289.2633400154. The cubic root of 18397780 is about 263.9906064916.

The spelling of 18397780 in words is "eighteen million, three hundred ninety-seven thousand, seven hundred eighty".