664666890 has 32 divisors (see below), whose sum is σ = 1638316800. Its totient is φ = 172453824.

The previous prime is 664666889. The next prime is 664666913. The reversal of 664666890 is 98666466.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 298290 + ... + 300509.

It is an arithmetic number, because the mean of its divisors is an integer number (51197400).

Almost surely, 2^664666890 is an apocalyptic number.

664666890 is an abundant number, since it is smaller than the sum of its proper divisors (973649910).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664666890 is a wasteful number, since it uses less digits than its factorization.

664666890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 598846.

The product of its (nonzero) digits is 2239488, while the sum is 51.

The square root of 664666890 is about 25781.1343815589. The cubic root of 664666890 is about 872.7061069776.

It can be divided in two parts, 6646 and 66890, that added together give a triangular number (73536 = T₃₈₃).

The spelling of 664666890 in words is "six hundred sixty-four million, six hundred sixty-six thousand, eight hundred ninety".