21463643 has 4 divisors (see below), whose sum is σ = 21815568. Its totient is φ = 21111720.

The previous prime is 21463633. The next prime is 21463649. The reversal of 21463643 is 34636412.

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 21463643 - 2¹² = 21459547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21463649) 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, 175871 + ... + 175992.

It is an arithmetic number, because the mean of its divisors is an integer number (5453892).

Almost surely, 2^21463643 is an apocalyptic number.

21463643 is a deficient number, since it is larger than the sum of its proper divisors (351925).

21463643 is an equidigital number, since it uses as much as digits as its factorization.

21463643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351924.

The product of its digits is 10368, while the sum is 29.

The square root of 21463643 is about 4632.8871128056. The cubic root of 21463643 is about 277.9080618295.

The spelling of 21463643 in words is "twenty-one million, four hundred sixty-three thousand, six hundred forty-three".