988634821 has 4 divisors (see below), whose sum is σ = 988723692. Its totient is φ = 988545952.

The previous prime is 988634749. The next prime is 988634827. The reversal of 988634821 is 128436889.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 794450596 + 194184225 = 28186^2 + 13935^2 .

It is a cyclic number.

It is not a de Polignac number, because 988634821 - 2²³ = 980246213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (988634827) by changing a digit.

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, 24880 + ... + 50953.

It is an arithmetic number, because the mean of its divisors is an integer number (247180923).

Almost surely, 2^988634821 is an apocalyptic number.

It is an amenable number.

988634821 is a deficient number, since it is larger than the sum of its proper divisors (88871).

988634821 is a wasteful number, since it uses less digits than its factorization.

988634821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88870.

The product of its digits is 663552, while the sum is 49.

The square root of 988634821 is about 31442.5638426640. The cubic root of 988634821 is about 996.1971637682.

It can be divided in two parts, 98863 and 4821, that added together give a square (103684 = 322²).

The spelling of 988634821 in words is "nine hundred eighty-eight million, six hundred thirty-four thousand, eight hundred twenty-one".