21001009989 has 8 divisors (see below), whose sum is σ = 28002190240. Its totient is φ = 14000251536.

The previous prime is 21001009973. The next prime is 21001009999. The reversal of 21001009989 is 98990010012.

It is a happy number.

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

It is not a de Polignac number, because 21001009989 - 2⁴ = 21001009973 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 (21001009999) 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 7 ways as a sum of consecutive naturals, for example, 38994 + ... + 208620.

It is an arithmetic number, because the mean of its divisors is an integer number (3500273780).

Almost surely, 2^21001009989 is an apocalyptic number.

It is an amenable number.

21001009989 is a deficient number, since it is larger than the sum of its proper divisors (7001180251).

21001009989 is a wasteful number, since it uses less digits than its factorization.

21001009989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210899.

The product of its (nonzero) digits is 11664, while the sum is 39.

The spelling of 21001009989 in words is "twenty-one billion, one million, nine thousand, nine hundred eighty-nine".