21594169 has 2 divisors, whose sum is σ = 21594170. Its totient is φ = 21594168.

The previous prime is 21594149. The next prime is 21594179. The reversal of 21594169 is 96149512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20142144 + 1452025 = 4488^2 + 1205^2 .

It is a cyclic number.

It is not a de Polignac number, because 21594169 - 2⁵ = 21594137 is a prime.

It is a super-2 number, since 2×21594169² = 932616269601122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21594149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10797084 + 10797085.

It is an arithmetic number, because the mean of its divisors is an integer number (10797085).

Almost surely, 2^21594169 is an apocalyptic number.

It is an amenable number.

21594169 is a deficient number, since it is larger than the sum of its proper divisors (1).

21594169 is an equidigital number, since it uses as much as digits as its factorization.

21594169 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 37.

The square root of 21594169 is about 4646.9526573874. The cubic root of 21594169 is about 278.4702674795.

It can be divided in two parts, 2159 and 4169, that added together give a triangular number (6328 = T₁₁₂).

The spelling of 21594169 in words is "twenty-one million, five hundred ninety-four thousand, one hundred sixty-nine".