32728721 has 2 divisors, whose sum is σ = 32728722. Its totient is φ = 32728720.

The previous prime is 32728711. The next prime is 32728727. The reversal of 32728721 is 12782723.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27415696 + 5313025 = 5236^2 + 2305^2 .

It is a cyclic number.

It is not a de Polignac number, because 32728721 - 2²² = 28534417 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (32728727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16364360 + 16364361.

It is an arithmetic number, because the mean of its divisors is an integer number (16364361).

Almost surely, 2^32728721 is an apocalyptic number.

It is an amenable number.

32728721 is a deficient number, since it is larger than the sum of its proper divisors (1).

32728721 is an equidigital number, since it uses as much as digits as its factorization.

32728721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9408, while the sum is 32.

The square root of 32728721 is about 5720.9021141774. The cubic root of 32728721 is about 319.8720875487.

The spelling of 32728721 in words is "thirty-two million, seven hundred twenty-eight thousand, seven hundred twenty-one".