38991 has 8 divisors (see below), whose sum is σ = 53424. Its totient is φ = 25280.

The previous prime is 38977. The next prime is 38993. The reversal of 38991 is 19983.

It is a happy number.

38991 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 38991 - 2⁵ = 38959 is a prime.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (38993) 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, 36 + ... + 281.

It is an arithmetic number, because the mean of its divisors is an integer number (6678).

2³⁸⁹⁹¹ is an apocalyptic number.

38991 is a deficient number, since it is larger than the sum of its proper divisors (14433).

38991 is a wasteful number, since it uses less digits than its factorization.

38991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361.

The product of its digits is 1944, while the sum is 30.

The square root of 38991 is about 197.4613886308. The cubic root of 38991 is about 33.9095056053.

The spelling of 38991 in words is "thirty-eight thousand, nine hundred ninety-one".