721986 has 8 divisors (see below), whose sum is σ = 1443984. Its totient is φ = 240660.

The previous prime is 721979. The next prime is 721991. The reversal of 721986 is 689127.

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

721986 is an admirable number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 721986.

It is an unprimeable number.

721986 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60160 + ... + 60171.

It is an arithmetic number, because the mean of its divisors is an integer number (180498).

2⁷²¹⁹⁸⁶ is an apocalyptic number.

721986 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

721986 is a wasteful number, since it uses less digits than its factorization.

721986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120336.

The product of its digits is 6048, while the sum is 33.

The square root of 721986 is about 849.6975932648. The cubic root of 721986 is about 89.7104273314.

The spelling of 721986 in words is "seven hundred twenty-one thousand, nine hundred eighty-six".