40161721 has 2 divisors, whose sum is σ = 40161722. Its totient is φ = 40161720.

The previous prime is 40161707. The next prime is 40161731. The reversal of 40161721 is 12716104.

40161721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28355625 + 11806096 = 5325^2 + 3436^2 .

It is a cyclic number.

It is not a de Polignac number, because 40161721 - 2⁷ = 40161593 is a prime.

It is a super-2 number, since 2×40161721² = 3225927667363682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 40161692 and 40161701.

It is not a weakly prime, because it can be changed into another prime (40161731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20080860 + 20080861.

It is an arithmetic number, because the mean of its divisors is an integer number (20080861).

Almost surely, 2^40161721 is an apocalyptic number.

It is an amenable number.

40161721 is a deficient number, since it is larger than the sum of its proper divisors (1).

40161721 is an equidigital number, since it uses as much as digits as its factorization.

40161721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 40161721 is about 6337.3275913432. The cubic root of 40161721 is about 342.4554679523.

Adding to 40161721 its reverse (12716104), we get a palindrome (52877825).

The spelling of 40161721 in words is "forty million, one hundred sixty-one thousand, seven hundred twenty-one".