39987920 has 90 divisors (see below), whose sum is σ = 109232406. Its totient is φ = 13574400.

The previous prime is 39987919. The next prime is 39987943. The reversal of 39987920 is 2978993.

It can be written as a sum of positive squares in 3 ways, for example, as 24840256 + 15147664 = 4984^2 + 3892^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 395870 + ... + 395970.

Almost surely, 2^39987920 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 39987920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (54616203).

39987920 is an abundant number, since it is smaller than the sum of its proper divisors (69244486).

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

39987920 is a wasteful number, since it uses less digits than its factorization.

39987920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 244944, while the sum is 47.

The square root of 39987920 is about 6323.6002403694. The cubic root of 39987920 is about 341.9607583533.

The spelling of 39987920 in words is "thirty-nine million, nine hundred eighty-seven thousand, nine hundred twenty".