21294421 has 8 divisors (see below), whose sum is σ = 23734080. Its totient is φ = 18986688.

The previous prime is 21294419. The next prime is 21294451. The reversal of 21294421 is 12449212.

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

It is not a de Polignac number, because 21294421 - 2¹ = 21294419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21294401) 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, 32641 + ... + 33286.

It is an arithmetic number, because the mean of its divisors is an integer number (2966760).

Almost surely, 2^21294421 is an apocalyptic number.

It is an amenable number.

21294421 is a deficient number, since it is larger than the sum of its proper divisors (2439659).

21294421 is a wasteful number, since it uses less digits than its factorization.

21294421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65963.

The product of its digits is 1152, while the sum is 25.

The square root of 21294421 is about 4614.5878472514. The cubic root of 21294421 is about 277.1757802038.

The spelling of 21294421 in words is "twenty-one million, two hundred ninety-four thousand, four hundred twenty-one".