21387284989 has 16 divisors (see below), whose sum is σ = 25247195136. Its totient is φ = 17729276400.

The previous prime is 21387284983. The next prime is 21387285037. The reversal of 21387284989 is 98948278312.

It is a cyclic number.

It is not a de Polignac number, because 21387284989 - 2⁵ = 21387284957 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 (21387284983) 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 15 ways as a sum of consecutive naturals, for example, 318054 + ... + 379384.

It is an arithmetic number, because the mean of its divisors is an integer number (1577949696).

Almost surely, 2^21387284989 is an apocalyptic number.

It is an amenable number.

21387284989 is a deficient number, since it is larger than the sum of its proper divisors (3859910147).

21387284989 is a wasteful number, since it uses less digits than its factorization.

21387284989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62976.

The product of its digits is 13934592, while the sum is 61.

The spelling of 21387284989 in words is "twenty-one billion, three hundred eighty-seven million, two hundred eighty-four thousand, nine hundred eighty-nine".