728791666 has 8 divisors (see below), whose sum is σ = 1157492700. Its totient is φ = 342960768.

The previous prime is 728791643. The next prime is 728791667. The reversal of 728791666 is 666197827.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 690165441 + 38626225 = 26271^2 + 6215^2 .

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

It is a super-2 number, since 2×728791666² = 1062274584862111112, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (728791667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10717491 + ... + 10717558.

Almost surely, 2^728791666 is an apocalyptic number.

728791666 is a deficient number, since it is larger than the sum of its proper divisors (428701034).

728791666 is a wasteful number, since it uses less digits than its factorization.

728791666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21435068.

The product of its digits is 1524096, while the sum is 52.

The square root of 728791666 is about 26996.1416872856. The cubic root of 728791666 is about 899.9142576753.

The spelling of 728791666 in words is "seven hundred twenty-eight million, seven hundred ninety-one thousand, six hundred sixty-six".