72517409 has 4 divisors (see below), whose sum is σ = 73885716. Its totient is φ = 71149104.

The previous prime is 72517399. The next prime is 72517439. The reversal of 72517409 is 90471527.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90471527 = 43 ⋅2103989.

It can be written as a sum of positive squares in 2 ways, for example, as 44849809 + 27667600 = 6697^2 + 5260^2 .

It is a cyclic number.

It is not a de Polignac number, because 72517409 - 2²⁴ = 55740193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72517439) 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, 684074 + ... + 684179.

It is an arithmetic number, because the mean of its divisors is an integer number (18471429).

Almost surely, 2^72517409 is an apocalyptic number.

It is an amenable number.

72517409 is a deficient number, since it is larger than the sum of its proper divisors (1368307).

72517409 is a wasteful number, since it uses less digits than its factorization.

72517409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1368306.

The product of its (nonzero) digits is 17640, while the sum is 35.

The square root of 72517409 is about 8515.7154132815. The cubic root of 72517409 is about 417.0109185570.

The spelling of 72517409 in words is "seventy-two million, five hundred seventeen thousand, four hundred nine".