21143442 has 16 divisors (see below), whose sum is σ = 42378912. Its totient is φ = 7032480.

The previous prime is 21143411. The next prime is 21143453. The reversal of 21143442 is 24434112.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 643 + ... + 6534.

It is an arithmetic number, because the mean of its divisors is an integer number (2648682).

Almost surely, 2^21143442 is an apocalyptic number.

21143442 is an abundant number, since it is smaller than the sum of its proper divisors (21235470).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21143442 is a wasteful number, since it uses less digits than its factorization.

21143442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7673.

The product of its digits is 768, while the sum is 21.

The square root of 21143442 is about 4598.1998651646. The cubic root of 21143442 is about 276.5191604148.

Adding to 21143442 its reverse (24434112), we get a palindrome (45577554).

The spelling of 21143442 in words is "twenty-one million, one hundred forty-three thousand, four hundred forty-two".