21021161 has 16 divisors (see below), whose sum is σ = 24630144. Its totient is φ = 17570304.

The previous prime is 21021157. The next prime is 21021181. The reversal of 21021161 is 16112012.

It is a cyclic number.

It is not a de Polignac number, because 21021161 - 2² = 21021157 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21021101) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56171 + ... + 56543.

It is an arithmetic number, because the mean of its divisors is an integer number (1539384).

Almost surely, 2^21021161 is an apocalyptic number.

It is an amenable number.

21021161 is a deficient number, since it is larger than the sum of its proper divisors (3608983).

21021161 is an equidigital number, since it uses as much as digits as its factorization.

21021161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560.

The product of its (nonzero) digits is 24, while the sum is 14.

The square root of 21021161 is about 4584.8839679974. The cubic root of 21021161 is about 275.9850557266.

Adding to 21021161 its reverse (16112012), we get a palindrome (37133173).

The spelling of 21021161 in words is "twenty-one million, twenty-one thousand, one hundred sixty-one".