72137909 has 2 divisors, whose sum is σ = 72137910. Its totient is φ = 72137908.

The previous prime is 72137893. The next prime is 72137911. The reversal of 72137909 is 90973127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61575409 + 10562500 = 7847^2 + 3250^2 .

It is a cyclic number.

It is not a de Polignac number, because 72137909 - 2⁴ = 72137893 is a prime.

Together with 72137911, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72137969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36068954 + 36068955.

It is an arithmetic number, because the mean of its divisors is an integer number (36068955).

Almost surely, 2^72137909 is an apocalyptic number.

It is an amenable number.

72137909 is a deficient number, since it is larger than the sum of its proper divisors (1).

72137909 is an equidigital number, since it uses as much as digits as its factorization.

72137909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23814, while the sum is 38.

The square root of 72137909 is about 8493.4038524022. The cubic root of 72137909 is about 416.2822084274.

The spelling of 72137909 in words is "seventy-two million, one hundred thirty-seven thousand, nine hundred nine".