21160221 has 4 divisors (see below), whose sum is σ = 28213632. Its totient is φ = 14106812.

The previous prime is 21160211. The next prime is 21160231. The reversal of 21160221 is 12206112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21160211) and next prime (21160231).

It is a cyclic number.

It is not a de Polignac number, because 21160221 - 2⁶ = 21160157 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21160221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21160211) 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 3 ways as a sum of consecutive naturals, for example, 3526701 + ... + 3526706.

It is an arithmetic number, because the mean of its divisors is an integer number (7053408).

Almost surely, 2^21160221 is an apocalyptic number.

It is an amenable number.

21160221 is a deficient number, since it is larger than the sum of its proper divisors (7053411).

21160221 is an equidigital number, since it uses as much as digits as its factorization.

21160221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7053410.

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 21160221 is about 4600.0240216764. The cubic root of 21160221 is about 276.5922877105.

Adding to 21160221 its reverse (12206112), we get a palindrome (33366333).

The spelling of 21160221 in words is "twenty-one million, one hundred sixty thousand, two hundred twenty-one".