666499722 has 64 divisors (see below), whose sum is σ = 1656702720. Its totient is φ = 174375936.

The previous prime is 666499679. The next prime is 666499741. The reversal of 666499722 is 227994666.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13804 + ... + 39032.

It is an arithmetic number, because the mean of its divisors is an integer number (25885980).

Almost surely, 2^666499722 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666499722, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (828351360).

666499722 is an abundant number, since it is smaller than the sum of its proper divisors (990202998).

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

666499722 is a wasteful number, since it uses less digits than its factorization.

666499722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25295.

The product of its digits is 1959552, while the sum is 51.

The square root of 666499722 is about 25816.6559027307. The cubic root of 666499722 is about 873.5075388489.

The spelling of 666499722 in words is "six hundred sixty-six million, four hundred ninety-nine thousand, seven hundred twenty-two".