21494421 has 12 divisors (see below), whose sum is σ = 33435948. Its totient is φ = 13227264.

The previous prime is 21494419. The next prime is 21494437. The reversal of 21494421 is 12449412.

It is a happy number.

21494421 is a `hidden beast` number, since 214 + 9 + 442 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13793796 + 7700625 = 3714^2 + 2775^2 .

It is not a de Polignac number, because 21494421 - 2¹ = 21494419 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21494411) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 91740 + ... + 91973.

It is an arithmetic number, because the mean of its divisors is an integer number (2786329).

Almost surely, 2^21494421 is an apocalyptic number.

It is an amenable number.

21494421 is a deficient number, since it is larger than the sum of its proper divisors (11941527).

21494421 is a wasteful number, since it uses less digits than its factorization.

21494421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183732 (or 183729 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21494421 is about 4636.2076096741. The cubic root of 21494421 is about 278.0408347103.

The spelling of 21494421 in words is "twenty-one million, four hundred ninety-four thousand, four hundred twenty-one".