646451878 has 8 divisors (see below), whose sum is σ = 971251272. Its totient is φ = 322701456.

The previous prime is 646451867. The next prime is 646451917. The reversal of 646451878 is 878154646.

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

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 260700 + ... + 263167.

It is an arithmetic number, because the mean of its divisors is an integer number (121406409).

Almost surely, 2^646451878 is an apocalyptic number.

646451878 is a deficient number, since it is larger than the sum of its proper divisors (324799394).

646451878 is a wasteful number, since it uses less digits than its factorization.

646451878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 524486.

The product of its digits is 1290240, while the sum is 49.

The square root of 646451878 is about 25425.4179513337. The cubic root of 646451878 is about 864.6600635591.

The spelling of 646451878 in words is "six hundred forty-six million, four hundred fifty-one thousand, eight hundred seventy-eight".