645047081 has 8 divisors (see below), whose sum is σ = 737530560. Its totient is φ = 552647088.

The previous prime is 645047077. The next prime is 645047083. The reversal of 645047081 is 180740546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 645047081 - 2² = 645047077 is a prime.

It is a super-2 number, since 2×645047081² = 832171473413241122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645047083) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3326 + ... + 36071.

It is an arithmetic number, because the mean of its divisors is an integer number (92191320).

Almost surely, 2^645047081 is an apocalyptic number.

It is an amenable number.

645047081 is a deficient number, since it is larger than the sum of its proper divisors (92483479).

645047081 is a wasteful number, since it uses less digits than its factorization.

645047081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41743.

The product of its (nonzero) digits is 26880, while the sum is 35.

The square root of 645047081 is about 25397.7770877689. Note that the first 3 decimals coincide. The cubic root of 645047081 is about 864.0332817719.

The spelling of 645047081 in words is "six hundred forty-five million, forty-seven thousand, eighty-one".