21320163 has 6 divisors (see below), whose sum is σ = 30795804. Its totient is φ = 14213436.

The previous prime is 21320107. The next prime is 21320183. The reversal of 21320163 is 36102312.

It is not a de Polignac number, because 21320163 - 2⁶ = 21320099 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21320183) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1184445 + ... + 1184462.

It is an arithmetic number, because the mean of its divisors is an integer number (5132634).

Almost surely, 2^21320163 is an apocalyptic number.

21320163 is a deficient number, since it is larger than the sum of its proper divisors (9475641).

21320163 is a wasteful number, since it uses less digits than its factorization.

21320163 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2368913 (or 2368910 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21320163 is about 4617.3762029967. The cubic root of 21320163 is about 277.2874242468.

Adding to 21320163 its reverse (36102312), we get a palindrome (57422475).

The spelling of 21320163 in words is "twenty-one million, three hundred twenty thousand, one hundred sixty-three".