39878640 has 120 divisors (see below), whose sum is σ = 135543408. Its totient is φ = 10506240.

The previous prime is 39878621. The next prime is 39878669. The reversal of 39878640 is 4687893.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (120).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 69555 + ... + 70125.

Almost surely, 2^39878640 is an apocalyptic number.

39878640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 39878640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67771704).

39878640 is an abundant number, since it is smaller than the sum of its proper divisors (95664768).

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

39878640 is a wasteful number, since it uses less digits than its factorization.

39878640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 687 (or 678 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 39878640 is about 6314.9536815403. The cubic root of 39878640 is about 341.6489678187.

The spelling of 39878640 in words is "thirty-nine million, eight hundred seventy-eight thousand, six hundred forty".