72256021 has 2 divisors, whose sum is σ = 72256022. Its totient is φ = 72256020.

The previous prime is 72256003. The next prime is 72256033. The reversal of 72256021 is 12065227.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62583921 + 9672100 = 7911^2 + 3110^2 .

It is a cyclic number.

It is not a de Polignac number, because 72256021 - 2⁹ = 72255509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72266021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36128010 + 36128011.

It is an arithmetic number, because the mean of its divisors is an integer number (36128011).

Almost surely, 2^72256021 is an apocalyptic number.

It is an amenable number.

72256021 is a deficient number, since it is larger than the sum of its proper divisors (1).

72256021 is an equidigital number, since it uses as much as digits as its factorization.

72256021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 72256021 is about 8500.3541690920. The cubic root of 72256021 is about 416.5092786549.

The spelling of 72256021 in words is "seventy-two million, two hundred fifty-six thousand, twenty-one".