72781889 has 2 divisors, whose sum is σ = 72781890. Its totient is φ = 72781888.

The previous prime is 72781861. The next prime is 72781921. The reversal of 72781889 is 98818727.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70425664 + 2356225 = 8392^2 + 1535^2 .

It is a cyclic number.

It is not a de Polignac number, because 72781889 - 2¹⁶ = 72716353 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (72781829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36390944 + 36390945.

It is an arithmetic number, because the mean of its divisors is an integer number (36390945).

Almost surely, 2^72781889 is an apocalyptic number.

It is an amenable number.

72781889 is a deficient number, since it is larger than the sum of its proper divisors (1).

72781889 is an equidigital number, since it uses as much as digits as its factorization.

72781889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 451584, while the sum is 50.

The square root of 72781889 is about 8531.2302160943. The cubic root of 72781889 is about 417.5172670258.

The spelling of 72781889 in words is "seventy-two million, seven hundred eighty-one thousand, eight hundred eighty-nine".