72256561 has 8 divisors (see below), whose sum is σ = 78618344. Its totient is φ = 66009600.

The previous prime is 72256559. The next prime is 72256571. The reversal of 72256561 is 16565227.

It can be written as a sum of positive squares in 4 ways, for example, as 6561 + 72250000 = 81^2 + 8500^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 72256561 - 2¹ = 72256559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72256571) 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 in 7 ways as a sum of consecutive naturals, for example, 27390 + ... + 29911.

It is an arithmetic number, because the mean of its divisors is an integer number (9827293).

Almost surely, 2^72256561 is an apocalyptic number.

It is an amenable number.

72256561 is a deficient number, since it is larger than the sum of its proper divisors (6361783).

72256561 is a wasteful number, since it uses less digits than its factorization.

72256561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57411.

The product of its digits is 25200, while the sum is 34.

The square root of 72256561 is about 8500.3859324151. The cubic root of 72256561 is about 416.5103162360.

It can be divided in two parts, 7225 and 6561, that multiplied together give a square (47403225 = 6885²).

The spelling of 72256561 in words is "seventy-two million, two hundred fifty-six thousand, five hundred sixty-one".