21712942 has 4 divisors (see below), whose sum is σ = 32569416. Its totient is φ = 10856470.

The previous prime is 21712939. The next prime is 21712949. The reversal of 21712942 is 24921712.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21712942.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21712949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5428234 + ... + 5428237.

It is an arithmetic number, because the mean of its divisors is an integer number (8142354).

Almost surely, 2^21712942 is an apocalyptic number.

21712942 is a deficient number, since it is larger than the sum of its proper divisors (10856474).

21712942 is a wasteful number, since it uses less digits than its factorization.

21712942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10856473.

The product of its digits is 2016, while the sum is 28.

The square root of 21712942 is about 4659.7147981395. The cubic root of 21712942 is about 278.9798848993.

The spelling of 21712942 in words is "twenty-one million, seven hundred twelve thousand, nine hundred forty-two".