406740721 has 4 divisors (see below), whose sum is σ = 409845744. Its totient is φ = 403635700.

The previous prime is 406740713. The next prime is 406740727. The reversal of 406740721 is 127047604.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 406740721 - 2³ = 406740713 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (406740727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1552315 + ... + 1552576.

It is an arithmetic number, because the mean of its divisors is an integer number (102461436).

Almost surely, 2^406740721 is an apocalyptic number.

It is an amenable number.

406740721 is a deficient number, since it is larger than the sum of its proper divisors (3105023).

406740721 is a wasteful number, since it uses less digits than its factorization.

406740721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3105022.

The product of its (nonzero) digits is 9408, while the sum is 31.

The square root of 406740721 is about 20167.8139866471. The cubic root of 406740721 is about 740.9221040926.

The spelling of 406740721 in words is "four hundred six million, seven hundred forty thousand, seven hundred twenty-one".