989105721 has 4 divisors (see below), whose sum is σ = 1318807632. Its totient is φ = 659403812.

The previous prime is 989105717. The next prime is 989105729. The reversal of 989105721 is 127501989.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 989105721 - 2² = 989105717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (989105729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164850951 + ... + 164850956.

It is an arithmetic number, because the mean of its divisors is an integer number (329701908).

Almost surely, 2^989105721 is an apocalyptic number.

It is an amenable number.

989105721 is a deficient number, since it is larger than the sum of its proper divisors (329701911).

989105721 is a wasteful number, since it uses less digits than its factorization.

989105721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329701910.

The product of its (nonzero) digits is 45360, while the sum is 42.

The square root of 989105721 is about 31450.0512082254. The cubic root of 989105721 is about 996.3553060108.

The spelling of 989105721 in words is "nine hundred eighty-nine million, one hundred five thousand, seven hundred twenty-one".