646473987 has 16 divisors (see below), whose sum is σ = 962560000. Its totient is φ = 428813352.

The previous prime is 646473983. The next prime is 646474007. The reversal of 646473987 is 789374646.

It is a happy number.

It is not a de Polignac number, because 646473987 - 2² = 646473983 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646473983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54787 + ... + 65532.

It is an arithmetic number, because the mean of its divisors is an integer number (60160000).

Almost surely, 2^646473987 is an apocalyptic number.

646473987 is a deficient number, since it is larger than the sum of its proper divisors (316086013).

646473987 is a wasteful number, since it uses less digits than its factorization.

646473987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120527 (or 120521 counting only the distinct ones).

The product of its digits is 6096384, while the sum is 54.

The square root of 646473987 is about 25425.8527290630. The cubic root of 646473987 is about 864.6699207256.

The spelling of 646473987 in words is "six hundred forty-six million, four hundred seventy-three thousand, nine hundred eighty-seven".