21426687 has 10 divisors (see below), whose sum is σ = 32007888. Its totient is φ = 14284404.

The previous prime is 21426683. The next prime is 21426697. The reversal of 21426687 is 78662412.

It is not a de Polignac number, because 21426687 - 2² = 21426683 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21426683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 132183 + ... + 132344.

Almost surely, 2^21426687 is an apocalyptic number.

21426687 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21426687 is a deficient number, since it is larger than the sum of its proper divisors (10581201).

21426687 is an equidigital number, since it uses as much as digits as its factorization.

21426687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 264539 (or 264530 counting only the distinct ones).

The product of its digits is 32256, while the sum is 36.

The square root of 21426687 is about 4628.8969528388. The cubic root of 21426687 is about 277.7484699331.

The spelling of 21426687 in words is "twenty-one million, four hundred twenty-six thousand, six hundred eighty-seven".