21342842 has 4 divisors (see below), whose sum is σ = 32014266. Its totient is φ = 10671420.

The previous prime is 21342829. The next prime is 21342851. The reversal of 21342842 is 24824312.

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., 15673681 + 5669161 = 3959^2 + 2381^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5335709 + ... + 5335712.

Almost surely, 2^21342842 is an apocalyptic number.

21342842 is a deficient number, since it is larger than the sum of its proper divisors (10671424).

21342842 is a wasteful number, since it uses less digits than its factorization.

21342842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10671423.

The product of its digits is 3072, while the sum is 26.

The square root of 21342842 is about 4619.8313822043. The cubic root of 21342842 is about 277.3857095024.

The spelling of 21342842 in words is "twenty-one million, three hundred forty-two thousand, eight hundred forty-two".