21570169 has 2 divisors, whose sum is σ = 21570170. Its totient is φ = 21570168.

The previous prime is 21570163. The next prime is 21570173. The reversal of 21570169 is 96107512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20142144 + 1428025 = 4488^2 + 1195^2 .

It is a cyclic number.

It is not a de Polignac number, because 21570169 - 2⁵ = 21570137 is a prime.

It is a super-2 number, since 2×21570169² = 930544381377122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21570169.

It is not a weakly prime, because it can be changed into another prime (21570163) 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, 10785084 + 10785085.

It is an arithmetic number, because the mean of its divisors is an integer number (10785085).

Almost surely, 2^21570169 is an apocalyptic number.

It is an amenable number.

21570169 is a deficient number, since it is larger than the sum of its proper divisors (1).

21570169 is an equidigital number, since it uses as much as digits as its factorization.

21570169 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3780, while the sum is 31.

The square root of 21570169 is about 4644.3696020020. The cubic root of 21570169 is about 278.3670642504.

The spelling of 21570169 in words is "twenty-one million, five hundred seventy thousand, one hundred sixty-nine".