72512309 has 4 divisors (see below), whose sum is σ = 73216416. Its totient is φ = 71808204.

The previous prime is 72512281. The next prime is 72512311. The reversal of 72512309 is 90321527.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 72512309 - 2⁸ = 72512053 is a prime.

It is a super-2 number, since 2×72512309² = 10516069913022962, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72512329) 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, 351899 + ... + 352104.

It is an arithmetic number, because the mean of its divisors is an integer number (18304104).

Almost surely, 2^72512309 is an apocalyptic number.

It is an amenable number.

72512309 is a deficient number, since it is larger than the sum of its proper divisors (704107).

72512309 is a wasteful number, since it uses less digits than its factorization.

72512309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 704106.

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 72512309 is about 8515.4159616545. The cubic root of 72512309 is about 417.0011424882.

The spelling of 72512309 in words is "seventy-two million, five hundred twelve thousand, three hundred nine".