21444028 has 6 divisors (see below), whose sum is σ = 37527056. Its totient is φ = 10722012.

The previous prime is 21444023. The next prime is 21444043. The reversal of 21444028 is 82044412.

It is a junction number, because it is equal to n+sod(n) for n = 21443993 and 21444011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2680500 + ... + 2680507.

Almost surely, 2^21444028 is an apocalyptic number.

It is an amenable number.

21444028 is a deficient number, since it is larger than the sum of its proper divisors (16083028).

21444028 is a wasteful number, since it uses less digits than its factorization.

21444028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5361011 (or 5361009 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 25.

The square root of 21444028 is about 4630.7696984411. The cubic root of 21444028 is about 277.8233786588.

The spelling of 21444028 in words is "twenty-one million, four hundred forty-four thousand, twenty-eight".