39991000 has 128 divisors (see below), whose sum is σ = 111196800. Its totient is φ = 13171200.

The previous prime is 39990983. The next prime is 39991009. The reversal of 39991000 is 19993.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39991009) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 202902 + ... + 203098.

It is an arithmetic number, because the mean of its divisors is an integer number (868725).

Almost surely, 2^39991000 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 39991000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55598400).

39991000 is an abundant number, since it is smaller than the sum of its proper divisors (71205800).

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

39991000 is a wasteful number, since it uses less digits than its factorization.

39991000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 2187, while the sum is 31.

The square root of 39991000 is about 6323.8437678361. The cubic root of 39991000 is about 341.9695377722.

The spelling of 39991000 in words is "thirty-nine million, nine hundred ninety-one thousand".