72642109 has 4 divisors (see below), whose sum is σ = 72667260. Its totient is φ = 72616960.

The previous prime is 72642079. The next prime is 72642113. The reversal of 72642109 is 90124627.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90124627 = 449 ⋅200723.

It can be written as a sum of positive squares in 2 ways, for example, as 35736484 + 36905625 = 5978^2 + 6075^2 .

It is a cyclic number.

It is not a de Polignac number, because 72642109 - 2⁵ = 72642077 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72648109) 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, 7582 + ... + 14239.

It is an arithmetic number, because the mean of its divisors is an integer number (18166815).

Almost surely, 2^72642109 is an apocalyptic number.

It is an amenable number.

72642109 is a deficient number, since it is larger than the sum of its proper divisors (25151).

72642109 is a wasteful number, since it uses less digits than its factorization.

72642109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25150.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 72642109 is about 8523.0340255099. The cubic root of 72642109 is about 417.2498105408.

The spelling of 72642109 in words is "seventy-two million, six hundred forty-two thousand, one hundred nine".