21309927 has 8 divisors (see below), whose sum is σ = 29329920. Its totient is φ = 13748280.

The previous prime is 21309913. The next prime is 21309973. The reversal of 21309927 is 72990312.

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

It is not a de Polignac number, because 21309927 - 2⁸ = 21309671 is a prime.

It is a super-2 number, since 2×21309927² = 908225977490658, which contains 22 as substring.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21309907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114477 + ... + 114662.

It is an arithmetic number, because the mean of its divisors is an integer number (3666240).

Almost surely, 2^21309927 is an apocalyptic number.

21309927 is a deficient number, since it is larger than the sum of its proper divisors (8019993).

21309927 is a wasteful number, since it uses less digits than its factorization.

21309927 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229173.

The product of its (nonzero) digits is 6804, while the sum is 33.

The square root of 21309927 is about 4616.2676482197. The cubic root of 21309927 is about 277.2430410898.

The spelling of 21309927 in words is "twenty-one million, three hundred nine thousand, nine hundred twenty-seven".