21790163 has 2 divisors, whose sum is σ = 21790164. Its totient is φ = 21790162.

The previous prime is 21790159. The next prime is 21790183. The reversal of 21790163 is 36109712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21790163 - 2² = 21790159 is a prime.

It is a super-2 number, since 2×21790163² = 949622407133138, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21790123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10895081 + 10895082.

It is an arithmetic number, because the mean of its divisors is an integer number (10895082).

Almost surely, 2^21790163 is an apocalyptic number.

21790163 is a deficient number, since it is larger than the sum of its proper divisors (1).

21790163 is an equidigital number, since it uses as much as digits as its factorization.

21790163 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 21790163 is about 4667.9934661480. The cubic root of 21790163 is about 279.3102196376.

Adding to 21790163 its reverse (36109712), we get a palindrome (57899875).

The spelling of 21790163 in words is "twenty-one million, seven hundred ninety thousand, one hundred sixty-three".