721366166 has 8 divisors (see below), whose sum is σ = 1083305664. Its totient is φ = 360264280.

The previous prime is 721366157. The next prime is 721366169. The reversal of 721366166 is 661663127.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721366169) 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, 207245 + ... + 210696.

It is an arithmetic number, because the mean of its divisors is an integer number (135413208).

Almost surely, 2^721366166 is an apocalyptic number.

721366166 is a deficient number, since it is larger than the sum of its proper divisors (361939498).

721366166 is a wasteful number, since it uses less digits than its factorization.

721366166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 418806.

The product of its digits is 54432, while the sum is 38.

The square root of 721366166 is about 26858.2606659478. The cubic root of 721366166 is about 896.8474747363.

The spelling of 721366166 in words is "seven hundred twenty-one million, three hundred sixty-six thousand, one hundred sixty-six".