21928669 has 8 divisors (see below), whose sum is σ = 25925760. Its totient is φ = 18147696.

The previous prime is 21928663. The next prime is 21928721. The reversal of 21928669 is 96682912.

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

It is not a de Polignac number, because 21928669 - 2⁷ = 21928541 is a prime.

It is a super-2 number, since 2×21928669² = 961733048223122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21928663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53809 + ... + 54214.

It is an arithmetic number, because the mean of its divisors is an integer number (3240720).

Almost surely, 2^21928669 is an apocalyptic number.

21928669 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21928669 is a deficient number, since it is larger than the sum of its proper divisors (3997091).

21928669 is a wasteful number, since it uses less digits than its factorization.

21928669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108059.

The product of its digits is 93312, while the sum is 43.

The square root of 21928669 is about 4682.8056760878. The cubic root of 21928669 is about 279.9007684081.

The spelling of 21928669 in words is "twenty-one million, nine hundred twenty-eight thousand, six hundred sixty-nine".