21716042 has 4 divisors (see below), whose sum is σ = 32574066. Its totient is φ = 10858020.

The previous prime is 21716033. The next prime is 21716047. The reversal of 21716042 is 24061712.

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., 17631601 + 4084441 = 4199^2 + 2021^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21715999 and 21716017.

It is not an unprimeable number, because it can be changed into a prime (21716047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5429009 + ... + 5429012.

Almost surely, 2^21716042 is an apocalyptic number.

21716042 is a deficient number, since it is larger than the sum of its proper divisors (10858024).

21716042 is a wasteful number, since it uses less digits than its factorization.

21716042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10858023.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 21716042 is about 4660.0474246514. The cubic root of 21716042 is about 278.9931611056.

Adding to 21716042 its reverse (24061712), we get a palindrome (45777754).

The spelling of 21716042 in words is "twenty-one million, seven hundred sixteen thousand, forty-two".