21079181 has 2 divisors, whose sum is σ = 21079182. Its totient is φ = 21079180.

The previous prime is 21079169. The next prime is 21079237. The reversal of 21079181 is 18197012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11055625 + 10023556 = 3325^2 + 3166^2 .

It is a cyclic number.

It is not a de Polignac number, because 21079181 - 2¹⁸ = 20817037 is a prime.

It is a super-2 number, since 2×21079181² = 888663743261522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21079141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10539590 + 10539591.

It is an arithmetic number, because the mean of its divisors is an integer number (10539591).

Almost surely, 2^21079181 is an apocalyptic number.

It is an amenable number.

21079181 is a deficient number, since it is larger than the sum of its proper divisors (1).

21079181 is an equidigital number, since it uses as much as digits as its factorization.

21079181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 29.

The square root of 21079181 is about 4591.2069219324. The cubic root of 21079181 is about 276.2387357118.

The spelling of 21079181 in words is "twenty-one million, seventy-nine thousand, one hundred eighty-one".