21308793 has 16 divisors (see below), whose sum is σ = 31071936. Its totient is φ = 12882240.

The previous prime is 21308789. The next prime is 21308801. The reversal of 21308793 is 39780312.

It is not a de Polignac number, because 21308793 - 2² = 21308789 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21308723) 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, 24555 + ... + 25407.

It is an arithmetic number, because the mean of its divisors is an integer number (1941996).

Almost surely, 2^21308793 is an apocalyptic number.

It is an amenable number.

21308793 is a deficient number, since it is larger than the sum of its proper divisors (9763143).

21308793 is a wasteful number, since it uses less digits than its factorization.

21308793 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1624.

The product of its (nonzero) digits is 9072, while the sum is 33.

The square root of 21308793 is about 4616.1448200853. The cubic root of 21308793 is about 277.2381232067.

The spelling of 21308793 in words is "twenty-one million, three hundred eight thousand, seven hundred ninety-three".