72015709 has 4 divisors (see below), whose sum is σ = 72128700. Its totient is φ = 71902720.

The previous prime is 72015707. The next prime is 72015733. The reversal of 72015709 is 90751027.

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

It can be written as a sum of positive squares in 2 ways, for example, as 60793209 + 11222500 = 7797^2 + 3350^2 .

It is a cyclic number.

It is not a de Polignac number, because 72015709 - 2¹ = 72015707 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72015701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55534 + ... + 56815.

It is an arithmetic number, because the mean of its divisors is an integer number (18032175).

Almost surely, 2^72015709 is an apocalyptic number.

It is an amenable number.

72015709 is a deficient number, since it is larger than the sum of its proper divisors (112991).

72015709 is a wasteful number, since it uses less digits than its factorization.

72015709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112990.

The product of its (nonzero) digits is 4410, while the sum is 31.

The square root of 72015709 is about 8486.2069854559. The cubic root of 72015709 is about 416.0470179999.

The spelling of 72015709 in words is "seventy-two million, fifteen thousand, seven hundred nine".