664861494 has 64 divisors (see below), whose sum is σ = 1493033472. Its totient is φ = 195628800.

The previous prime is 664861489. The next prime is 664861499. The reversal of 664861494 is 494168466.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (664861489) and next prime (664861499).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664861499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 749119 + ... + 750005.

It is an arithmetic number, because the mean of its divisors is an integer number (23328648).

Almost surely, 2^664861494 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664861494, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (746516736).

664861494 is an abundant number, since it is smaller than the sum of its proper divisors (828171978).

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

664861494 is a wasteful number, since it uses less digits than its factorization.

664861494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1221.

The product of its digits is 995328, while the sum is 48.

The square root of 664861494 is about 25784.9082604534. The cubic root of 664861494 is about 872.7912702024.

The spelling of 664861494 in words is "six hundred sixty-four million, eight hundred sixty-one thousand, four hundred ninety-four".