409505861 has 4 divisors (see below), whose sum is σ = 409559724. Its totient is φ = 409452000.

The previous prime is 409505857. The next prime is 409505903. The reversal of 409505861 is 168505904.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 38365636 + 371140225 = 6194^2 + 19265^2 .

It is a cyclic number.

It is not a de Polignac number, because 409505861 - 2² = 409505857 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (409505851) 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, 13190 + ... + 31511.

It is an arithmetic number, because the mean of its divisors is an integer number (102389931).

Almost surely, 2^409505861 is an apocalyptic number.

It is an amenable number.

409505861 is a deficient number, since it is larger than the sum of its proper divisors (53863).

409505861 is an equidigital number, since it uses as much as digits as its factorization.

409505861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53862.

The product of its (nonzero) digits is 43200, while the sum is 38.

The square root of 409505861 is about 20236.2511597381. The cubic root of 409505861 is about 742.5973138975.

The spelling of 409505861 in words is "four hundred nine million, five hundred five thousand, eight hundred sixty-one".