21162643 has 8 divisors (see below), whose sum is σ = 21734208. Its totient is φ = 20596224.

The previous prime is 21162641. The next prime is 21162653. The reversal of 21162643 is 34626112.

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

It is a cyclic number.

It is not a de Polignac number, because 21162643 - 2¹ = 21162641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21162641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7905 + ... + 10237.

It is an arithmetic number, because the mean of its divisors is an integer number (2716776).

Almost surely, 2^21162643 is an apocalyptic number.

21162643 is a deficient number, since it is larger than the sum of its proper divisors (571565).

21162643 is a wasteful number, since it uses less digits than its factorization.

21162643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2573.

The product of its digits is 1728, while the sum is 25.

The square root of 21162643 is about 4600.2872736385. The cubic root of 21162643 is about 276.6028402305.

Adding to 21162643 its reverse (34626112), we get a palindrome (55788755).

The spelling of 21162643 in words is "twenty-one million, one hundred sixty-two thousand, six hundred forty-three".