39720091 has 4 divisors (see below), whose sum is σ = 39898432. Its totient is φ = 39541752.

The previous prime is 39720073. The next prime is 39720113. The reversal of 39720091 is 19002793.

39720091 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 39720091 - 2⁵ = 39720059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39720001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 88836 + ... + 89281.

It is an arithmetic number, because the mean of its divisors is an integer number (9974608).

Almost surely, 2^39720091 is an apocalyptic number.

39720091 is a deficient number, since it is larger than the sum of its proper divisors (178341).

39720091 is a wasteful number, since it uses less digits than its factorization.

39720091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178340.

The product of its (nonzero) digits is 3402, while the sum is 31.

The square root of 39720091 is about 6302.3877221256. The cubic root of 39720091 is about 341.1955918750.

The spelling of 39720091 in words is "thirty-nine million, seven hundred twenty thousand, ninety-one".