21986667 has 16 divisors (see below), whose sum is σ = 34288000. Its totient is φ = 13885992.

The previous prime is 21986639. The next prime is 21986683. The reversal of 21986667 is 76668912.

It is not a de Polignac number, because 21986667 - 2¹⁰ = 21985643 is a prime.

It is a Duffinian number.

It is a plaindrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (21986687) 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 15 ways as a sum of consecutive naturals, for example, 20917 + ... + 21942.

It is an arithmetic number, because the mean of its divisors is an integer number (2143000).

Almost surely, 2^21986667 is an apocalyptic number.

21986667 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21986667 is a deficient number, since it is larger than the sum of its proper divisors (12301333).

21986667 is a wasteful number, since it uses less digits than its factorization.

21986667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42887 (or 42881 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The square root of 21986667 is about 4688.9942418391. The cubic root of 21986667 is about 280.1473161865.

The spelling of 21986667 in words is "twenty-one million, nine hundred eighty-six thousand, six hundred sixty-seven".