72822721 has 2 divisors, whose sum is σ = 72822722. Its totient is φ = 72822720.

The previous prime is 72822719. The next prime is 72822727. The reversal of 72822721 is 12722827.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46444225 + 26378496 = 6815^2 + 5136^2 .

It is a cyclic number.

It is not a de Polignac number, because 72822721 - 2¹ = 72822719 is a prime.

Together with 72822719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (72822727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36411360 + 36411361.

It is an arithmetic number, because the mean of its divisors is an integer number (36411361).

Almost surely, 2^72822721 is an apocalyptic number.

It is an amenable number.

72822721 is a deficient number, since it is larger than the sum of its proper divisors (1).

72822721 is an equidigital number, since it uses as much as digits as its factorization.

72822721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6272, while the sum is 31.

The square root of 72822721 is about 8533.6229703450. The cubic root of 72822721 is about 417.5953307593.

The spelling of 72822721 in words is "seventy-two million, eight hundred twenty-two thousand, seven hundred twenty-one".