987830721 has 22 divisors (see below), whose sum is σ = 1481826290. Its totient is φ = 658514448.

The previous prime is 987830719. The next prime is 987830731. The reversal of 987830721 is 127038789.

It can be written as a sum of positive squares in only one way, i.e., 893352321 + 94478400 = 29889^2 + 9720^2 .

It is not a de Polignac number, because 987830721 - 2¹ = 987830719 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (987830731) by changing a digit.

It is a polite number, since it can be written in 21 ways as a sum of consecutive naturals, for example, 50685 + ... + 67413.

Almost surely, 2^987830721 is an apocalyptic number.

It is an amenable number.

987830721 is a deficient number, since it is larger than the sum of its proper divisors (493995569).

987830721 is an frugal number, since it uses more digits than its factorization.

987830721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16759 (or 16732 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The square root of 987830721 is about 31429.7744344435. The cubic root of 987830721 is about 995.9270069167.

The spelling of 987830721 in words is "nine hundred eighty-seven million, eight hundred thirty thousand, seven hundred twenty-one".