72709831 has 4 divisors (see below), whose sum is σ = 75871152. Its totient is φ = 69548512.

The previous prime is 72709829. The next prime is 72709837. The reversal of 72709831 is 13890727.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13890727 = 881 ⋅15767.

It is a cyclic number.

It is not a de Polignac number, because 72709831 - 2¹ = 72709829 is a prime.

It is a super-2 number, since 2×72709831² = 10573439048097122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72709837) 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, 1580626 + ... + 1580671.

It is an arithmetic number, because the mean of its divisors is an integer number (18967788).

Almost surely, 2^72709831 is an apocalyptic number.

72709831 is a deficient number, since it is larger than the sum of its proper divisors (3161321).

72709831 is a wasteful number, since it uses less digits than its factorization.

72709831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3161320.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 72709831 is about 8527.0059809994. The cubic root of 72709831 is about 417.3794333154.

The spelling of 72709831 in words is "seventy-two million, seven hundred nine thousand, eight hundred thirty-one".