646547771 has 4 divisors (see below), whose sum is σ = 654732000. Its totient is φ = 638363544.

The previous prime is 646547761. The next prime is 646547801. The reversal of 646547771 is 177745646.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646547771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646547761) 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, 4091996 + ... + 4092153.

It is an arithmetic number, because the mean of its divisors is an integer number (163683000).

Almost surely, 2^646547771 is an apocalyptic number.

646547771 is a deficient number, since it is larger than the sum of its proper divisors (8184229).

646547771 is an equidigital number, since it uses as much as digits as its factorization.

646547771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8184228.

The product of its digits is 987840, while the sum is 47.

The square root of 646547771 is about 25427.3036517835. The cubic root of 646547771 is about 864.7028152579.

The spelling of 646547771 in words is "six hundred forty-six million, five hundred forty-seven thousand, seven hundred seventy-one".