72691 has 4 divisors (see below), whose sum is σ = 73312. Its totient is φ = 72072.

The previous prime is 72689. The next prime is 72701. The reversal of 72691 is 19627.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 19627 = 19 ⋅1033.

It is a cyclic number.

It is not a de Polignac number, because 72691 - 2¹ = 72689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75 + ... + 388.

It is an arithmetic number, because the mean of its divisors is an integer number (18328).

2⁷²⁶⁹¹ is an apocalyptic number.

72691 is a deficient number, since it is larger than the sum of its proper divisors (621).

72691 is a wasteful number, since it uses less digits than its factorization.

72691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 620.

The product of its digits is 756, while the sum is 25.

The square root of 72691 is about 269.6126851615. The cubic root of 72691 is about 41.7343398066.

It can be divided in two parts, 726 and 91, that multiplied together give a palindrome (66066).

The spelling of 72691 in words is "seventy-two thousand, six hundred ninety-one".