21212927 has 4 divisors (see below), whose sum is σ = 21263736. Its totient is φ = 21162120.

The previous prime is 21212909. The next prime is 21212941. The reversal of 21212927 is 72921212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21212927 - 2¹⁶ = 21147391 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21212896 and 21212905.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24773 + ... + 25614.

It is an arithmetic number, because the mean of its divisors is an integer number (5315934).

Almost surely, 2^21212927 is an apocalyptic number.

21212927 is a deficient number, since it is larger than the sum of its proper divisors (50809).

21212927 is an equidigital number, since it uses as much as digits as its factorization.

21212927 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50808.

The product of its digits is 1008, while the sum is 26.

The square root of 21212927 is about 4605.7493418552. The cubic root of 21212927 is about 276.8217431924.

The spelling of 21212927 in words is "twenty-one million, two hundred twelve thousand, nine hundred twenty-seven".