21287463 has 8 divisors (see below), whose sum is σ = 28441728. Its totient is φ = 14162424.

The previous prime is 21287459. The next prime is 21287531. The reversal of 21287463 is 36478212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21287463 - 2² = 21287459 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21287423) 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 7 ways as a sum of consecutive naturals, for example, 5545 + ... + 8562.

It is an arithmetic number, because the mean of its divisors is an integer number (3555216).

Almost surely, 2^21287463 is an apocalyptic number.

21287463 is a deficient number, since it is larger than the sum of its proper divisors (7154265).

21287463 is a wasteful number, since it uses less digits than its factorization.

21287463 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14613.

The product of its digits is 16128, while the sum is 33.

The square root of 21287463 is about 4613.8338721718. The cubic root of 21287463 is about 277.1455876450.

It can be divided in two parts, 2128 and 7463, that added together give a triangular number (9591 = T₁₃₈).

The spelling of 21287463 in words is "twenty-one million, two hundred eighty-seven thousand, four hundred sixty-three".