71728561 has 2 divisors, whose sum is σ = 71728562. Its totient is φ = 71728560.

The previous prime is 71728543. The next prime is 71728567. The reversal of 71728561 is 16582717.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70560000 + 1168561 = 8400^2 + 1081^2 .

It is a cyclic number.

It is not a de Polignac number, because 71728561 - 2⁵ = 71728529 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 71728561.

It is not a weakly prime, because it can be changed into another prime (71728567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35864280 + 35864281.

It is an arithmetic number, because the mean of its divisors is an integer number (35864281).

Almost surely, 2^71728561 is an apocalyptic number.

It is an amenable number.

71728561 is a deficient number, since it is larger than the sum of its proper divisors (1).

71728561 is an equidigital number, since it uses as much as digits as its factorization.

71728561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23520, while the sum is 37.

The square root of 71728561 is about 8469.2715743445. The cubic root of 71728561 is about 415.4933137826.

The spelling of 71728561 in words is "seventy-one million, seven hundred twenty-eight thousand, five hundred sixty-one".