21419921 has 8 divisors (see below), whose sum is σ = 22014720. Its totient is φ = 20831008.

The previous prime is 21419911. The next prime is 21419927. The reversal of 21419921 is 12991412.

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

It is a cyclic number.

It is not a de Polignac number, because 21419921 - 2⁶ = 21419857 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21419927) 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, 6485 + ... + 9213.

It is an arithmetic number, because the mean of its divisors is an integer number (2751840).

Almost surely, 2^21419921 is an apocalyptic number.

It is an amenable number.

21419921 is a deficient number, since it is larger than the sum of its proper divisors (594799).

21419921 is a wasteful number, since it uses less digits than its factorization.

21419921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2943.

The product of its digits is 1296, while the sum is 29.

The square root of 21419921 is about 4628.1660514722. The cubic root of 21419921 is about 277.7192315665.

The spelling of 21419921 in words is "twenty-one million, four hundred nineteen thousand, nine hundred twenty-one".