21079969 has 4 divisors (see below), whose sum is σ = 21760000. Its totient is φ = 20399940.

The previous prime is 21079931. The next prime is 21079979. The reversal of 21079969 is 96997012.

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 not a de Polignac number, because 21079969 - 2¹⁷ = 20948897 is a prime.

It is a super-2 number, since 2×21079969² = 888730186081922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21079979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 339969 + ... + 340030.

It is an arithmetic number, because the mean of its divisors is an integer number (5440000).

Almost surely, 2^21079969 is an apocalyptic number.

It is an amenable number.

21079969 is a deficient number, since it is larger than the sum of its proper divisors (680031).

21079969 is an equidigital number, since it uses as much as digits as its factorization.

21079969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 680030.

The product of its (nonzero) digits is 61236, while the sum is 43.

The square root of 21079969 is about 4591.2927373453. The cubic root of 21079969 is about 276.2421778666.

The spelling of 21079969 in words is "twenty-one million, seventy-nine thousand, nine hundred sixty-nine".