21712424 has 16 divisors (see below), whose sum is σ = 40821300. Its totient is φ = 10826752.

The previous prime is 21712423. The next prime is 21712469. The reversal of 21712424 is 42421712.

It can be written as a sum of positive squares in 2 ways, for example, as 19802500 + 1909924 = 4450^2 + 1382^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21712424.

It is not an unprimeable number, because it can be changed into a prime (21712423) 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 in 3 ways as a sum of consecutive naturals, for example, 377 + ... + 6600.

Almost surely, 2^21712424 is an apocalyptic number.

It is an amenable number.

21712424 is a deficient number, since it is larger than the sum of its proper divisors (19108876).

21712424 is a wasteful number, since it uses less digits than its factorization.

21712424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7372 (or 7368 counting only the distinct ones).

The product of its digits is 896, while the sum is 23.

The square root of 21712424 is about 4659.6592150070. The cubic root of 21712424 is about 278.9776663649.

The spelling of 21712424 in words is "twenty-one million, seven hundred twelve thousand, four hundred twenty-four".