72021539 has 2 divisors, whose sum is σ = 72021540. Its totient is φ = 72021538.

The previous prime is 72021527. The next prime is 72021557. The reversal of 72021539 is 93512027.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 72021539 - 2⁸ = 72021283 is a prime.

It is not a weakly prime, because it can be changed into another prime (72021139) 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, 36010769 + 36010770.

It is an arithmetic number, because the mean of its divisors is an integer number (36010770).

Almost surely, 2^72021539 is an apocalyptic number.

72021539 is a deficient number, since it is larger than the sum of its proper divisors (1).

72021539 is an equidigital number, since it uses as much as digits as its factorization.

72021539 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 72021539 is about 8486.5504770784. The cubic root of 72021539 is about 416.0582446646.

The spelling of 72021539 in words is "seventy-two million, twenty-one thousand, five hundred thirty-nine".