21062687 has 4 divisors (see below), whose sum is σ = 21978480. Its totient is φ = 20146896.

The previous prime is 21062683. The next prime is 21062689. The reversal of 21062687 is 78626012.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21062687 - 2² = 21062683 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21062681) 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, 457862 + ... + 457907.

It is an arithmetic number, because the mean of its divisors is an integer number (5494620).

Almost surely, 2^21062687 is an apocalyptic number.

21062687 is a deficient number, since it is larger than the sum of its proper divisors (915793).

21062687 is an equidigital number, since it uses as much as digits as its factorization.

21062687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 915792.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 21062687 is about 4589.4103107044. The cubic root of 21062687 is about 276.1666666464.

Adding to 21062687 its reverse (78626012), we get a palindrome (99688699).

The spelling of 21062687 in words is "twenty-one million, sixty-two thousand, six hundred eighty-seven".