721206166 has 8 divisors (see below), whose sum is σ = 1082374704. Its totient is φ = 360414600.

The previous prime is 721206137. The next prime is 721206217. The reversal of 721206166 is 661602127.

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 an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 89410 + ... + 97141.

It is an arithmetic number, because the mean of its divisors is an integer number (135296838).

Almost surely, 2^721206166 is an apocalyptic number.

721206166 is a deficient number, since it is larger than the sum of its proper divisors (361168538).

721206166 is a wasteful number, since it uses less digits than its factorization.

721206166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188486.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 721206166 is about 26855.2819013318. The cubic root of 721206166 is about 896.7811625021.

It can be divided in two parts, 7212061 and 66, that added together give a palindrome (7212127).

The spelling of 721206166 in words is "seven hundred twenty-one million, two hundred six thousand, one hundred sixty-six".