39990640 has 20 divisors (see below), whose sum is σ = 92978424. Its totient is φ = 15996224.

The previous prime is 39990607. The next prime is 39990653. The reversal of 39990640 is 4609993.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 39990593 and 39990602.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 249862 + ... + 250021.

Almost surely, 2^39990640 is an apocalyptic number.

It is an amenable number.

39990640 is an abundant number, since it is smaller than the sum of its proper divisors (52987784).

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

39990640 is a wasteful number, since it uses less digits than its factorization.

39990640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499896 (or 499890 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 40.

The square root of 39990640 is about 6323.8153040708. The cubic root of 39990640 is about 341.9685116296.

The spelling of 39990640 in words is "thirty-nine million, nine hundred ninety thousand, six hundred forty".