505645691 has 4 divisors (see below), whose sum is σ = 506465832. Its totient is φ = 504825552.

The previous prime is 505645687. The next prime is 505645703. The reversal of 505645691 is 196546505.

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

It is a cyclic number.

It is not a de Polignac number, because 505645691 - 2² = 505645687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (505641691) 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, 409145 + ... + 410378.

It is an arithmetic number, because the mean of its divisors is an integer number (126616458).

Almost surely, 2^505645691 is an apocalyptic number.

505645691 is a deficient number, since it is larger than the sum of its proper divisors (820141).

505645691 is an equidigital number, since it uses as much as digits as its factorization.

505645691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 820140.

The product of its (nonzero) digits is 162000, while the sum is 41.

The square root of 505645691 is about 22486.5669011523. The cubic root of 505645691 is about 796.6766775895.

The spelling of 505645691 in words is "five hundred five million, six hundred forty-five thousand, six hundred ninety-one".