21388428789 has 16 divisors (see below), whose sum is σ = 35098960512. Its totient is φ = 11281808448.

The previous prime is 21388428781. The next prime is 21388428797. The reversal of 21388428789 is 98782488312.

It is an interprime number because it is at equal distance from previous prime (21388428781) and next prime (21388428797).

It is not a de Polignac number, because 21388428789 - 2³ = 21388428781 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21388428781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39172674 + ... + 39173219.

It is an arithmetic number, because the mean of its divisors is an integer number (2193685032).

Almost surely, 2^21388428789 is an apocalyptic number.

It is an amenable number.

21388428789 is a deficient number, since it is larger than the sum of its proper divisors (13710531723).

21388428789 is a wasteful number, since it uses less digits than its factorization.

21388428789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78345916.

The product of its digits is 12386304, while the sum is 60.

The spelling of 21388428789 in words is "twenty-one billion, three hundred eighty-eight million, four hundred twenty-eight thousand, seven hundred eighty-nine".