21055769 has 8 divisors (see below), whose sum is σ = 24893760. Its totient is φ = 17425296.

The previous prime is 21055763. The next prime is 21055799. The reversal of 21055769 is 96755012.

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

It is not a de Polignac number, because 21055769 - 2⁸ = 21055513 is a prime.

It is a super-2 number, since 2×21055769² = 886690816362722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21055763) 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, 51659 + ... + 52064.

It is an arithmetic number, because the mean of its divisors is an integer number (3111720).

Almost surely, 2^21055769 is an apocalyptic number.

21055769 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21055769 is a deficient number, since it is larger than the sum of its proper divisors (3837991).

21055769 is a wasteful number, since it uses less digits than its factorization.

21055769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103759.

The product of its (nonzero) digits is 18900, while the sum is 35.

The square root of 21055769 is about 4588.6565572071. The cubic root of 21055769 is about 276.1364278612.

The spelling of 21055769 in words is "twenty-one million, fifty-five thousand, seven hundred sixty-nine".