21290065 has 8 divisors (see below), whose sum is σ = 26659008. Its totient is φ = 16291440.

The previous prime is 21290039. The next prime is 21290083. The reversal of 21290065 is 56009212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21290065 - 2¹⁵ = 21257297 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 92451 + ... + 92680.

It is an arithmetic number, because the mean of its divisors is an integer number (3332376).

Almost surely, 2^21290065 is an apocalyptic number.

It is an amenable number.

21290065 is a deficient number, since it is larger than the sum of its proper divisors (5368943).

21290065 is a wasteful number, since it uses less digits than its factorization.

21290065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185159.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 21290065 is about 4614.1158416321. The cubic root of 21290065 is about 277.1568791649.

Adding to 21290065 its reverse (56009212), we get a palindrome (77299277).

The spelling of 21290065 in words is "twenty-one million, two hundred ninety thousand, sixty-five".