72004021 has 2 divisors, whose sum is σ = 72004022. Its totient is φ = 72004020.

The previous prime is 72003989. The next prime is 72004033. The reversal of 72004021 is 12040027.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37075921 + 34928100 = 6089^2 + 5910^2 .

It is an emirp because it is prime and its reverse (12040027) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72004021 - 2⁵ = 72003989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 72003986 and 72004004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72004321) 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, 36002010 + 36002011.

It is an arithmetic number, because the mean of its divisors is an integer number (36002011).

Almost surely, 2^72004021 is an apocalyptic number.

It is an amenable number.

72004021 is a deficient number, since it is larger than the sum of its proper divisors (1).

72004021 is an equidigital number, since it uses as much as digits as its factorization.

72004021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 16.

The square root of 72004021 is about 8485.5183106278. The cubic root of 72004021 is about 416.0245089265.

Adding to 72004021 its reverse (12040027), we get a palindrome (84044048).

The spelling of 72004021 in words is "seventy-two million, four thousand, twenty-one".