40397721 has 16 divisors (see below), whose sum is σ = 66294144. Its totient is φ = 21308544.

The previous prime is 40397719. The next prime is 40397737. The reversal of 40397721 is 12779304.

40397721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 40397721 - 2¹ = 40397719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (40397701) 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 15 ways as a sum of consecutive naturals, for example, 73716 + ... + 74261.

It is an arithmetic number, because the mean of its divisors is an integer number (4143384).

Almost surely, 2^40397721 is an apocalyptic number.

It is an amenable number.

40397721 is a deficient number, since it is larger than the sum of its proper divisors (25896423).

40397721 is a wasteful number, since it uses less digits than its factorization.

40397721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148000.

The product of its (nonzero) digits is 10584, while the sum is 33.

The square root of 40397721 is about 6355.9201536835. The cubic root of 40397721 is about 343.1249420871.

The spelling of 40397721 in words is "forty million, three hundred ninety-seven thousand, seven hundred twenty-one".