72781999 has 2 divisors, whose sum is σ = 72782000. Its totient is φ = 72781998.

The previous prime is 72781993. The next prime is 72782041. The reversal of 72781999 is 99918727.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 72781999 - 2¹³ = 72773807 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72781993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36390999 + 36391000.

It is an arithmetic number, because the mean of its divisors is an integer number (36391000).

Almost surely, 2^72781999 is an apocalyptic number.

72781999 is a deficient number, since it is larger than the sum of its proper divisors (1).

72781999 is an equidigital number, since it uses as much as digits as its factorization.

72781999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 571536, while the sum is 52.

The square root of 72781999 is about 8531.2366629932. The cubic root of 72781999 is about 417.5174773660.

The spelling of 72781999 in words is "seventy-two million, seven hundred eighty-one thousand, nine hundred ninety-nine".