39390721 has 8 divisors (see below), whose sum is σ = 40088160. Its totient is φ = 38698752.

The previous prime is 39390643. The next prime is 39390731. The reversal of 39390721 is 12709393.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 39390721 - 2⁹ = 39390209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39390731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14790 + ... + 17248.

It is an arithmetic number, because the mean of its divisors is an integer number (5011020).

Almost surely, 2^39390721 is an apocalyptic number.

It is an amenable number.

39390721 is a deficient number, since it is larger than the sum of its proper divisors (697439).

39390721 is a wasteful number, since it uses less digits than its factorization.

39390721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2735.

The product of its (nonzero) digits is 10206, while the sum is 34.

The square root of 39390721 is about 6276.2027532577. The cubic root of 39390721 is about 340.2498768662.

The spelling of 39390721 in words is "thirty-nine million, three hundred ninety thousand, seven hundred twenty-one".