72449921 has 2 divisors, whose sum is σ = 72449922. Its totient is φ = 72449920.

The previous prime is 72449893. The next prime is 72449933. The reversal of 72449921 is 12994427.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60450625 + 11999296 = 7775^2 + 3464^2 .

It is an emirp because it is prime and its reverse (12994427) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72449921 - 2²⁶ = 5341057 is a prime.

It is not a weakly prime, because it can be changed into another prime (72449941) 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, 36224960 + 36224961.

It is an arithmetic number, because the mean of its divisors is an integer number (36224961).

Almost surely, 2^72449921 is an apocalyptic number.

It is an amenable number.

72449921 is a deficient number, since it is larger than the sum of its proper divisors (1).

72449921 is an equidigital number, since it uses as much as digits as its factorization.

72449921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 38.

The square root of 72449921 is about 8511.7519348252. The cubic root of 72449921 is about 416.8815152949.

The spelling of 72449921 in words is "seventy-two million, four hundred forty-nine thousand, nine hundred twenty-one".