21802643 has 8 divisors (see below), whose sum is σ = 22809600. Its totient is φ = 20800648.

The previous prime is 21802621. The next prime is 21802661. The reversal of 21802643 is 34620812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21802643 - 2⁸ = 21802387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21802243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10028 + ... + 12006.

It is an arithmetic number, because the mean of its divisors is an integer number (2851200).

Almost surely, 2^21802643 is an apocalyptic number.

21802643 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21802643 is a deficient number, since it is larger than the sum of its proper divisors (1006957).

21802643 is a wasteful number, since it uses less digits than its factorization.

21802643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2481.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 21802643 is about 4669.3300375964. The cubic root of 21802643 is about 279.3635330872.

The spelling of 21802643 in words is "twenty-one million, eight hundred two thousand, six hundred forty-three".