21279193 has 8 divisors (see below), whose sum is σ = 22985928. Its totient is φ = 19582464.

The previous prime is 21279187. The next prime is 21279199. The reversal of 21279193 is 39197212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21279187) and next prime (21279199).

It can be written as a sum of positive squares in 4 ways, for example, as 8649 + 21270544 = 93^2 + 4612^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21279193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21279199) 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, 2271 + ... + 6907.

It is an arithmetic number, because the mean of its divisors is an integer number (2873241).

Almost surely, 2^21279193 is an apocalyptic number.

It is an amenable number.

21279193 is a deficient number, since it is larger than the sum of its proper divisors (1706735).

21279193 is a wasteful number, since it uses less digits than its factorization.

21279193 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5003.

The product of its digits is 6804, while the sum is 34.

The square root of 21279193 is about 4612.9375673208. The cubic root of 21279193 is about 277.1096934212.

The spelling of 21279193 in words is "twenty-one million, two hundred seventy-nine thousand, one hundred ninety-three".