21079305 has 32 divisors (see below), whose sum is σ = 40360320. Its totient is φ = 10376640.

The previous prime is 21079297. The next prime is 21079309. The reversal of 21079305 is 50397012.

It is not a de Polignac number, because 21079305 - 2³ = 21079297 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21079309) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4251 + ... + 7760.

It is an arithmetic number, because the mean of its divisors is an integer number (1261260).

Almost surely, 2^21079305 is an apocalyptic number.

It is an amenable number.

21079305 is a deficient number, since it is larger than the sum of its proper divisors (19281015).

21079305 is a wasteful number, since it uses less digits than its factorization.

21079305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12038 (or 12032 counting only the distinct ones).

The product of its (nonzero) digits is 1890, while the sum is 27.

The square root of 21079305 is about 4591.2204259870. The cubic root of 21079305 is about 276.2392773764.

The spelling of 21079305 in words is "twenty-one million, seventy-nine thousand, three hundred five".