72819997 has 4 divisors (see below), whose sum is σ = 72852316. Its totient is φ = 72787680.

The previous prime is 72819979. The next prime is 72820009. The reversal of 72819997 is 79991827.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 39803481 + 33016516 = 6309^2 + 5746^2 .

It is a cyclic number.

It is not a de Polignac number, because 72819997 - 2¹⁵ = 72787229 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72819907) 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 in 3 ways as a sum of consecutive naturals, for example, 12504 + ... + 17377.

It is an arithmetic number, because the mean of its divisors is an integer number (18213079).

Almost surely, 2^72819997 is an apocalyptic number.

It is an amenable number.

72819997 is a deficient number, since it is larger than the sum of its proper divisors (32319).

72819997 is a wasteful number, since it uses less digits than its factorization.

72819997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32318.

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

The square root of 72819997 is about 8533.4633648947. The cubic root of 72819997 is about 417.5901238502.

The spelling of 72819997 in words is "seventy-two million, eight hundred nineteen thousand, nine hundred ninety-seven".