21331042 has 4 divisors (see below), whose sum is σ = 31996566. Its totient is φ = 10665520.

The previous prime is 21331021. The next prime is 21331043. The reversal of 21331042 is 24013312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 17214201 + 4116841 = 4149^2 + 2029^2 .

It is not an unprimeable number, because it can be changed into a prime (21331043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5332759 + ... + 5332762.

Almost surely, 2^21331042 is an apocalyptic number.

21331042 is a deficient number, since it is larger than the sum of its proper divisors (10665524).

21331042 is a wasteful number, since it uses less digits than its factorization.

21331042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10665523.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21331042 is about 4618.5541027469. The cubic root of 21331042 is about 277.3345798735.

Adding to 21331042 its reverse (24013312), we get a palindrome (45344354).

The spelling of 21331042 in words is "twenty-one million, three hundred thirty-one thousand, forty-two".