72138889 has 2 divisors, whose sum is σ = 72138890. Its totient is φ = 72138888.

The previous prime is 72138881. The next prime is 72138901. The reversal of 72138889 is 98883127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61465600 + 10673289 = 7840^2 + 3267^2 .

It is a cyclic number.

It is not a de Polignac number, because 72138889 - 2³ = 72138881 is a prime.

It is not a weakly prime, because it can be changed into another prime (72138881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36069444 + 36069445.

It is an arithmetic number, because the mean of its divisors is an integer number (36069445).

Almost surely, 2^72138889 is an apocalyptic number.

It is an amenable number.

72138889 is a deficient number, since it is larger than the sum of its proper divisors (1).

72138889 is an equidigital number, since it uses as much as digits as its factorization.

72138889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 193536, while the sum is 46.

The square root of 72138889 is about 8493.4615440349. The cubic root of 72138889 is about 416.2840934959.

The spelling of 72138889 in words is "seventy-two million, one hundred thirty-eight thousand, eight hundred eighty-nine".