40804021 has 2 divisors, whose sum is σ = 40804022. Its totient is φ = 40804020.

The previous prime is 40804013. The next prime is 40804031. The reversal of 40804021 is 12040804.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30371121 + 10432900 = 5511^2 + 3230^2 .

It is a cyclic number.

It is not a de Polignac number, because 40804021 - 2³ = 40804013 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 40804021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40804031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20402010 + 20402011.

It is an arithmetic number, because the mean of its divisors is an integer number (20402011).

Almost surely, 2^40804021 is an apocalyptic number.

It is an amenable number.

40804021 is a deficient number, since it is larger than the sum of its proper divisors (1).

40804021 is an equidigital number, since it uses as much as digits as its factorization.

40804021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 40804021 is about 6387.8025172981. The cubic root of 40804021 is about 344.2714331688.

Adding to 40804021 its reverse (12040804), we get a palindrome (52844825).

The spelling of 40804021 in words is "forty million, eight hundred four thousand, twenty-one".