72665431 has 4 divisors (see below), whose sum is σ = 74211552. Its totient is φ = 71119312.

The previous prime is 72665413. The next prime is 72665449. The reversal of 72665431 is 13456627.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13456627 = 157 ⋅85711.

It is an interprime number because it is at equal distance from previous prime (72665413) and next prime (72665449).

It is a cyclic number.

It is not a de Polignac number, because 72665431 - 2¹³ = 72657239 is a prime.

It is a super-2 number, since 2×72665431² = 10560529724831522, 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 (72665401) 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, 772990 + ... + 773083.

It is an arithmetic number, because the mean of its divisors is an integer number (18552888).

Almost surely, 2^72665431 is an apocalyptic number.

72665431 is a deficient number, since it is larger than the sum of its proper divisors (1546121).

72665431 is a wasteful number, since it uses less digits than its factorization.

72665431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1546120.

The product of its digits is 30240, while the sum is 34.

The square root of 72665431 is about 8524.4020904695. The cubic root of 72665431 is about 417.2944589272.

The spelling of 72665431 in words is "seventy-two million, six hundred sixty-five thousand, four hundred thirty-one".