388891091 has 4 divisors (see below), whose sum is σ = 389160192. Its totient is φ = 388621992.

The previous prime is 388891067. The next prime is 388891121. The reversal of 388891091 is 190198883.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-388891091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (388891021) 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, 132371 + ... + 135276.

It is an arithmetic number, because the mean of its divisors is an integer number (97290048).

Almost surely, 2^388891091 is an apocalyptic number.

388891091 is a deficient number, since it is larger than the sum of its proper divisors (269101).

388891091 is a wasteful number, since it uses less digits than its factorization.

388891091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269100.

The product of its (nonzero) digits is 124416, while the sum is 47.

The square root of 388891091 is about 19720.3217772936. The cubic root of 388891091 is about 729.9212343865.

The spelling of 388891091 in words is "three hundred eighty-eight million, eight hundred ninety-one thousand, ninety-one".