21892643 has 4 divisors (see below), whose sum is σ = 21911040. Its totient is φ = 21874248.

The previous prime is 21892601. The next prime is 21892649. The reversal of 21892643 is 34629812.

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 21892643 - 2¹⁶ = 21827107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21892649) 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, 7280 + ... + 9837.

It is an arithmetic number, because the mean of its divisors is an integer number (5477760).

Almost surely, 2^21892643 is an apocalyptic number.

21892643 is a deficient number, since it is larger than the sum of its proper divisors (18397).

21892643 is a wasteful number, since it uses less digits than its factorization.

21892643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18396.

The product of its digits is 20736, while the sum is 35.

The square root of 21892643 is about 4678.9574693515. The cubic root of 21892643 is about 279.7474039972.

The spelling of 21892643 in words is "twenty-one million, eight hundred ninety-two thousand, six hundred forty-three".