18381929091 has 4 divisors (see below), whose sum is σ = 24509238792. Its totient is φ = 12254619392.

The previous prime is 18381929087. The next prime is 18381929101. The reversal of 18381929091 is 19092918381.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19092918381 = 3 ⋅6364306127.

It is a cyclic number.

It is not a de Polignac number, because 18381929091 - 2² = 18381929087 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18381939091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3063654846 + ... + 3063654851.

It is an arithmetic number, because the mean of its divisors is an integer number (6127309698).

Almost surely, 2^18381929091 is an apocalyptic number.

18381929091 is a deficient number, since it is larger than the sum of its proper divisors (6127309701).

18381929091 is an equidigital number, since it uses as much as digits as its factorization.

18381929091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6127309700.

The product of its (nonzero) digits is 279936, while the sum is 51.

The spelling of 18381929091 in words is "eighteen billion, three hundred eighty-one million, nine hundred twenty-nine thousand, ninety-one".