21654789 has 8 divisors (see below), whose sum is σ = 31094112. Its totient is φ = 13326000.

The previous prime is 21654781. The next prime is 21654791. The reversal of 21654789 is 98745612.

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

It is not a de Polignac number, because 21654789 - 2³ = 21654781 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 21654789.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21654781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 277587 + ... + 277664.

It is an arithmetic number, because the mean of its divisors is an integer number (3886764).

Almost surely, 2^21654789 is an apocalyptic number.

It is an amenable number.

21654789 is a deficient number, since it is larger than the sum of its proper divisors (9439323).

21654789 is a wasteful number, since it uses less digits than its factorization.

21654789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555267.

The product of its digits is 120960, while the sum is 42.

The square root of 21654789 is about 4653.4706402856. The cubic root of 21654789 is about 278.7306015847.

The spelling of 21654789 in words is "twenty-one million, six hundred fifty-four thousand, seven hundred eighty-nine".