21166463 has 4 divisors (see below), whose sum is σ = 22086768. Its totient is φ = 20246160.

The previous prime is 21166447. The next prime is 21166471. The reversal of 21166463 is 36466112.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21166463 - 2⁴ = 21166447 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 (21166163) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 460118 + ... + 460163.

It is an arithmetic number, because the mean of its divisors is an integer number (5521692).

Almost surely, 2^21166463 is an apocalyptic number.

21166463 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21166463 is a deficient number, since it is larger than the sum of its proper divisors (920305).

21166463 is an equidigital number, since it uses as much as digits as its factorization.

21166463 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 920304.

The product of its digits is 5184, while the sum is 29.

The square root of 21166463 is about 4600.7024463662. The cubic root of 21166463 is about 276.6194821228.

The spelling of 21166463 in words is "twenty-one million, one hundred sixty-six thousand, four hundred sixty-three".