9819689021 has 4 divisors (see below), whose sum is σ = 9853203612. Its totient is φ = 9786174432.

The previous prime is 9819688999. The next prime is 9819689071. The reversal of 9819689021 is 1209869189.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8876277796 + 943411225 = 94214^2 + 30715^2 .

It is a cyclic number.

It is not a de Polignac number, because 9819689021 - 2²⁶ = 9752580157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9819689071) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16756856 + ... + 16757441.

It is an arithmetic number, because the mean of its divisors is an integer number (2463300903).

Almost surely, 2^9819689021 is an apocalyptic number.

It is an amenable number.

9819689021 is a deficient number, since it is larger than the sum of its proper divisors (33514591).

9819689021 is a wasteful number, since it uses less digits than its factorization.

9819689021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33514590.

The product of its (nonzero) digits is 559872, while the sum is 53.

The square root of 9819689021 is about 99094.3440414235. The cubic root of 9819689021 is about 2141.4071320989.

The spelling of 9819689021 in words is "nine billion, eight hundred nineteen million, six hundred eighty-nine thousand, twenty-one".