21055793 has 4 divisors (see below), whose sum is σ = 22969968. Its totient is φ = 19141620.

The previous prime is 21055763. The next prime is 21055799. The reversal of 21055793 is 39755012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21055793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21055799) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 957071 + ... + 957092.

It is an arithmetic number, because the mean of its divisors is an integer number (5742492).

Almost surely, 2^21055793 is an apocalyptic number.

It is an amenable number.

21055793 is a deficient number, since it is larger than the sum of its proper divisors (1914175).

21055793 is a wasteful number, since it uses less digits than its factorization.

21055793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1914174.

The product of its (nonzero) digits is 9450, while the sum is 32.

The square root of 21055793 is about 4588.6591723509. The cubic root of 21055793 is about 276.1365327773.

The spelling of 21055793 in words is "twenty-one million, fifty-five thousand, seven hundred ninety-three".