72307681 has 4 divisors (see below), whose sum is σ = 76561092. Its totient is φ = 68054272.

The previous prime is 72307679. The next prime is 72307693. The reversal of 72307681 is 18670327.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 31539456 + 40768225 = 5616^2 + 6385^2 .

It is a cyclic number.

It is not a de Polignac number, because 72307681 - 2¹ = 72307679 is a prime.

It is a super-2 number, since 2×72307681² = 10456801463195522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72307601) 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, 2126680 + ... + 2126713.

It is an arithmetic number, because the mean of its divisors is an integer number (19140273).

Almost surely, 2^72307681 is an apocalyptic number.

It is an amenable number.

72307681 is a deficient number, since it is larger than the sum of its proper divisors (4253411).

72307681 is a wasteful number, since it uses less digits than its factorization.

72307681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4253410.

The product of its (nonzero) digits is 14112, while the sum is 34.

The square root of 72307681 is about 8503.3923230673. The cubic root of 72307681 is about 416.6085171829.

The spelling of 72307681 in words is "seventy-two million, three hundred seven thousand, six hundred eighty-one".