40857809 has 4 divisors (see below), whose sum is σ = 43008240. Its totient is φ = 38707380.

The previous prime is 40857793. The next prime is 40857811. The reversal of 40857809 is 90875804.

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 40857809 - 2⁴ = 40857793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40857889) 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, 1075187 + ... + 1075224.

It is an arithmetic number, because the mean of its divisors is an integer number (10752060).

Almost surely, 2^40857809 is an apocalyptic number.

It is an amenable number.

40857809 is a deficient number, since it is larger than the sum of its proper divisors (2150431).

40857809 is a wasteful number, since it uses less digits than its factorization.

40857809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2150430.

The product of its (nonzero) digits is 80640, while the sum is 41.

The square root of 40857809 is about 6392.0113422928. The cubic root of 40857809 is about 344.4226400080.

The spelling of 40857809 in words is "forty million, eight hundred fifty-seven thousand, eight hundred nine".