18780381 has 12 divisors (see below), whose sum is σ = 27243840. Its totient is φ = 12466440.

The previous prime is 18780347. The next prime is 18780383. The reversal of 18780381 is 18308781.

It is not a de Polignac number, because 18780381 - 2²¹ = 16683229 is a prime.

It is a super-2 number, since 2×18780381² = 705405421010322, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18780383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2215 + ... + 6516.

It is an arithmetic number, because the mean of its divisors is an integer number (2270320).

Almost surely, 2^18780381 is an apocalyptic number.

It is an amenable number.

18780381 is a deficient number, since it is larger than the sum of its proper divisors (8463459).

18780381 is a wasteful number, since it uses less digits than its factorization.

18780381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8976 (or 8973 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 36.

The square root of 18780381 is about 4333.6336947186. The cubic root of 18780381 is about 265.8080521113.

The spelling of 18780381 in words is "eighteen million, seven hundred eighty thousand, three hundred eighty-one".