39999990 has 64 divisors (see below), whose sum is σ = 103680000. Its totient is φ = 9846144.

The previous prime is 39999983. The next prime is 40000003. The reversal of 39999990 is 9999993.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 39999990.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19011 + ... + 21009.

It is an arithmetic number, because the mean of its divisors is an integer number (1620000).

Almost surely, 2^39999990 is an apocalyptic number.

39999990 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 39999990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51840000).

39999990 is an abundant number, since it is smaller than the sum of its proper divisors (63680010).

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

39999990 is a wasteful number, since it uses less digits than its factorization.

39999990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2061.

The product of its (nonzero) digits is 1594323, while the sum is 57.

The square root of 39999990 is about 6324.5545297673. The cubic root of 39999990 is about 341.9951608357.

The spelling of 39999990 in words is "thirty-nine million, nine hundred ninety-nine thousand, nine hundred ninety".