72687691 has 2 divisors, whose sum is σ = 72687692. Its totient is φ = 72687690.

The previous prime is 72687689. The next prime is 72687707. The reversal of 72687691 is 19678627.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 72687691 - 2¹ = 72687689 is a prime.

It is a super-2 number, since 2×72687691² = 10567000845822962, which contains 22 as substring.

Together with 72687689, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (72687611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36343845 + 36343846.

It is an arithmetic number, because the mean of its divisors is an integer number (36343846).

Almost surely, 2^72687691 is an apocalyptic number.

72687691 is a deficient number, since it is larger than the sum of its proper divisors (1).

72687691 is an equidigital number, since it uses as much as digits as its factorization.

72687691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 46.

The square root of 72687691 is about 8525.7076539135. The cubic root of 72687691 is about 417.3370652770.

The spelling of 72687691 in words is "seventy-two million, six hundred eighty-seven thousand, six hundred ninety-one".