72891731 has 6 divisors (see below), whose sum is σ = 80120796. Its totient is φ = 66265100.

The previous prime is 72891701. The next prime is 72891769. The reversal of 72891731 is 13719827.

It is not a de Polignac number, because 72891731 - 2¹⁸ = 72629587 is a prime.

It is a super-2 number, since 2×72891731² = 10626408896352722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72891701) 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 5 ways as a sum of consecutive naturals, for example, 301085 + ... + 301326.

It is an arithmetic number, because the mean of its divisors is an integer number (13353466).

Almost surely, 2^72891731 is an apocalyptic number.

72891731 is a deficient number, since it is larger than the sum of its proper divisors (7229065).

72891731 is a wasteful number, since it uses less digits than its factorization.

72891731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 602433 (or 602422 counting only the distinct ones).

The product of its digits is 21168, while the sum is 38.

The square root of 72891731 is about 8537.6654303152. The cubic root of 72891731 is about 417.7271996550.

The spelling of 72891731 in words is "seventy-two million, eight hundred ninety-one thousand, seven hundred thirty-one".