40842721 has 8 divisors (see below), whose sum is σ = 43307784. Its totient is φ = 38384640.

The previous prime is 40842713. The next prime is 40842727. The reversal of 40842721 is 12724804.

It can be written as a sum of positive squares in 4 ways, for example, as 583696 + 40259025 = 764^2 + 6345^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 40842721 - 2³ = 40842713 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 40842721.

It is not an unprimeable number, because it can be changed into a prime (40842727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14941 + ... + 17461.

It is an arithmetic number, because the mean of its divisors is an integer number (5413473).

Almost surely, 2^40842721 is an apocalyptic number.

It is an amenable number.

40842721 is a deficient number, since it is larger than the sum of its proper divisors (2465063).

40842721 is a wasteful number, since it uses less digits than its factorization.

40842721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3491.

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 40842721 is about 6390.8310101269. The cubic root of 40842721 is about 344.3802385778.

The spelling of 40842721 in words is "forty million, eight hundred forty-two thousand, seven hundred twenty-one".