38991645 has 128 divisors (see below), whose sum is σ = 89948160. Its totient is φ = 15681600.

The previous prime is 38991613. The next prime is 38991649. The reversal of 38991645 is 54619983.

It is a happy number.

It is not a de Polignac number, because 38991645 - 2⁵ = 38991613 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 38991645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (38991649) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1257780 + ... + 1257810.

It is an arithmetic number, because the mean of its divisors is an integer number (702720).

Almost surely, 2^38991645 is an apocalyptic number.

38991645 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

It is an amenable number.

38991645 is an abundant number, since it is smaller than the sum of its proper divisors (50956515).

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

38991645 is a wasteful number, since it uses less digits than its factorization.

38991645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85 (or 57 counting only the distinct ones).

The product of its digits is 233280, while the sum is 45.

The square root of 38991645 is about 6244.3290272054. The cubic root of 38991645 is about 339.0969258440.

The spelling of 38991645 in words is "thirty-eight million, nine hundred ninety-one thousand, six hundred forty-five".