987721 has 8 divisors (see below), whose sum is σ = 1137600. Its totient is φ = 840048.

The previous prime is 987713. The next prime is 987739. The reversal of 987721 is 127789.

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

It is a cyclic number.

It is not a de Polignac number, because 987721 - 2³ = 987713 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (987821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 570 + ... + 1516.

It is an arithmetic number, because the mean of its divisors is an integer number (142200).

2⁹⁸⁷⁷²¹ is an apocalyptic number.

It is an amenable number.

987721 is a deficient number, since it is larger than the sum of its proper divisors (149879).

987721 is a wasteful number, since it uses less digits than its factorization.

987721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1103.

The product of its digits is 7056, while the sum is 34.

The square root of 987721 is about 993.8415366647. The cubic root of 987721 is about 99.5890132126.

The spelling of 987721 in words is "nine hundred eighty-seven thousand, seven hundred twenty-one".