21716487 has 24 divisors (see below), whose sum is σ = 35562800. Its totient is φ = 12659328.

The previous prime is 21716479. The next prime is 21716489. The reversal of 21716487 is 78461712.

21716487 is a `hidden beast` number, since 2 + 1 + 7 + 1 + 648 + 7 = 666.

It is not a de Polignac number, because 21716487 - 2³ = 21716479 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21716489) by changing a digit.

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 in 23 ways as a sum of consecutive naturals, for example, 2662 + ... + 7107.

Almost surely, 2^21716487 is an apocalyptic number.

21716487 is a deficient number, since it is larger than the sum of its proper divisors (13846313).

21716487 is a wasteful number, since it uses less digits than its factorization.

21716487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9807 (or 9804 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 21716487 is about 4660.0951707020. The cubic root of 21716487 is about 278.9950667798.

The spelling of 21716487 in words is "twenty-one million, seven hundred sixteen thousand, four hundred eighty-seven".