40345721 has 12 divisors (see below), whose sum is σ = 45861732. Its totient is φ = 35277984.

The previous prime is 40345717. The next prime is 40345729. The reversal of 40345721 is 12754304.

40345721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 16687225 + 23658496 = 4085^2 + 4864^2 .

It is not a de Polignac number, because 40345721 - 2² = 40345717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40345729) 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 in 11 ways as a sum of consecutive naturals, for example, 395 + ... + 8991.

It is an arithmetic number, because the mean of its divisors is an integer number (3821811).

Almost surely, 2^40345721 is an apocalyptic number.

It is an amenable number.

40345721 is a deficient number, since it is larger than the sum of its proper divisors (5516011).

40345721 is a wasteful number, since it uses less digits than its factorization.

40345721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8648 (or 8629 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 40345721 is about 6351.8281620334. The cubic root of 40345721 is about 342.9776552464.

The spelling of 40345721 in words is "forty million, three hundred forty-five thousand, seven hundred twenty-one".