21849161 has 2 divisors, whose sum is σ = 21849162. Its totient is φ = 21849160.

The previous prime is 21849137. The next prime is 21849167. The reversal of 21849161 is 16194812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20757136 + 1092025 = 4556^2 + 1045^2 .

It is a cyclic number.

It is not a de Polignac number, because 21849161 - 2¹⁸ = 21587017 is a prime.

It is not a weakly prime, because it can be changed into another prime (21849167) 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 as a sum of consecutive naturals, namely, 10924580 + 10924581.

It is an arithmetic number, because the mean of its divisors is an integer number (10924581).

Almost surely, 2^21849161 is an apocalyptic number.

It is an amenable number.

21849161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21849161 is an equidigital number, since it uses as much as digits as its factorization.

21849161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 32.

The square root of 21849161 is about 4674.3086119767. The cubic root of 21849161 is about 279.5620747876.

The spelling of 21849161 in words is "twenty-one million, eight hundred forty-nine thousand, one hundred sixty-one".