40721165 has 4 divisors (see below), whose sum is σ = 48865404. Its totient is φ = 32576928.

The previous prime is 40721089. The next prime is 40721167. The reversal of 40721165 is 56112704.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 31787044 + 8934121 = 5638^2 + 2989^2 .

It is a cyclic number.

It is not a de Polignac number, because 40721165 - 2¹² = 40717069 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40721167) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4072112 + ... + 4072121.

It is an arithmetic number, because the mean of its divisors is an integer number (12216351).

Almost surely, 2^40721165 is an apocalyptic number.

It is an amenable number.

40721165 is a deficient number, since it is larger than the sum of its proper divisors (8144239).

40721165 is an equidigital number, since it uses as much as digits as its factorization.

40721165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8144238.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 40721165 is about 6381.3137362145. The cubic root of 40721165 is about 344.0382512224.

Adding to 40721165 its reverse (56112704), we get a palindrome (96833869).

The spelling of 40721165 in words is "forty million, seven hundred twenty-one thousand, one hundred sixty-five".