21287622 has 16 divisors (see below), whose sum is σ = 42724080. Its totient is φ = 7071072.

The previous prime is 21287551. The next prime is 21287633. The reversal of 21287622 is 22678212.

It is a self number, because there is not a number n which added to its sum of digits gives 21287622.

It is a congruent number.

It is an unprimeable number.

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, 4297 + ... + 7812.

It is an arithmetic number, because the mean of its divisors is an integer number (2670255).

Almost surely, 2^21287622 is an apocalyptic number.

21287622 is an abundant number, since it is smaller than the sum of its proper divisors (21436458).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21287622 is a wasteful number, since it uses less digits than its factorization.

21287622 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12407.

The product of its digits is 5376, while the sum is 30.

The square root of 21287622 is about 4613.8511029291. The cubic root of 21287622 is about 277.1462776605.

It can be divided in two parts, 2128762 and 2, that multiplied together give a palindrome (4257524).

The spelling of 21287622 in words is "twenty-one million, two hundred eighty-seven thousand, six hundred twenty-two".