40828721 has 2 divisors, whose sum is σ = 40828722. Its totient is φ = 40828720.

The previous prime is 40828717. The next prime is 40828751. The reversal of 40828721 is 12782804.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39828721 + 1000000 = 6311^2 + 1000^2 .

It is a cyclic number.

It is not a de Polignac number, because 40828721 - 2² = 40828717 is a prime.

It is not a weakly prime, because it can be changed into another prime (40828751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20414360 + 20414361.

It is an arithmetic number, because the mean of its divisors is an integer number (20414361).

Almost surely, 2^40828721 is an apocalyptic number.

It is an amenable number.

40828721 is a deficient number, since it is larger than the sum of its proper divisors (1).

40828721 is an equidigital number, since it uses as much as digits as its factorization.

40828721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 40828721 is about 6389.7355970337. The cubic root of 40828721 is about 344.3408853858.

The spelling of 40828721 in words is "forty million, eight hundred twenty-eight thousand, seven hundred twenty-one".