21142444 has 6 divisors (see below), whose sum is σ = 36999284. Its totient is φ = 10571220.

The previous prime is 21142439. The next prime is 21142447. The reversal of 21142444 is 44424112.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21142447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2642802 + ... + 2642809.

Almost surely, 2^21142444 is an apocalyptic number.

It is an amenable number.

21142444 is a deficient number, since it is larger than the sum of its proper divisors (15856840).

21142444 is a wasteful number, since it uses less digits than its factorization.

21142444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5285615 (or 5285613 counting only the distinct ones).

The product of its digits is 1024, while the sum is 22.

The square root of 21142444 is about 4598.0913431553. The cubic root of 21142444 is about 276.5148096494.

Adding to 21142444 its reverse (44424112), we get a palindrome (65566556).

The spelling of 21142444 in words is "twenty-one million, one hundred forty-two thousand, four hundred forty-four".