40121665 has 4 divisors (see below), whose sum is σ = 48146004. Its totient is φ = 32097328.

The previous prime is 40121663. The next prime is 40121681. The reversal of 40121665 is 56612104.

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 7219969 + 32901696 = 2687^2 + 5736^2 .

It is a cyclic number.

It is not a de Polignac number, because 40121665 - 2¹ = 40121663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40121663) 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, 4012162 + ... + 4012171.

It is an arithmetic number, because the mean of its divisors is an integer number (12036501).

Almost surely, 2^40121665 is an apocalyptic number.

It is an amenable number.

40121665 is a deficient number, since it is larger than the sum of its proper divisors (8024339).

40121665 is an equidigital number, since it uses as much as digits as its factorization.

40121665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8024338.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 40121665 is about 6334.1664802877. The cubic root of 40121665 is about 342.3415787494.

Adding to 40121665 its reverse (56612104), we get a palindrome (96733769).

The spelling of 40121665 in words is "forty million, one hundred twenty-one thousand, six hundred sixty-five".