21245161 has 8 divisors (see below), whose sum is σ = 24324480. Its totient is φ = 18176928.

The previous prime is 21245153. The next prime is 21245167. The reversal of 21245161 is 16154212.

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

It is not a de Polignac number, because 21245161 - 2³ = 21245153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21245167) 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 7 ways as a sum of consecutive naturals, for example, 1860 + ... + 6778.

It is an arithmetic number, because the mean of its divisors is an integer number (3040560).

Almost surely, 2^21245161 is an apocalyptic number.

It is an amenable number.

21245161 is a deficient number, since it is larger than the sum of its proper divisors (3079319).

21245161 is an equidigital number, since it uses as much as digits as its factorization.

21245161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5543.

The product of its digits is 480, while the sum is 22.

The square root of 21245161 is about 4609.2473355202. The cubic root of 21245161 is about 276.9618866092.

Adding to 21245161 its reverse (16154212), we get a palindrome (37399373).

The spelling of 21245161 in words is "twenty-one million, two hundred forty-five thousand, one hundred sixty-one".