72726821 has 2 divisors, whose sum is σ = 72726822. Its totient is φ = 72726820.

The previous prime is 72726781. The next prime is 72726869. The reversal of 72726821 is 12862727.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44742721 + 27984100 = 6689^2 + 5290^2 .

It is a cyclic number.

It is not a de Polignac number, because 72726821 - 2⁶ = 72726757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72026821) 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, 36363410 + 36363411.

It is an arithmetic number, because the mean of its divisors is an integer number (36363411).

Almost surely, 2^72726821 is an apocalyptic number.

It is an amenable number.

72726821 is a deficient number, since it is larger than the sum of its proper divisors (1).

72726821 is an equidigital number, since it uses as much as digits as its factorization.

72726821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18816, while the sum is 35.

The square root of 72726821 is about 8528.0021693243. The cubic root of 72726821 is about 417.4119402644.

The spelling of 72726821 in words is "seventy-two million, seven hundred twenty-six thousand, eight hundred twenty-one".