21136361 has 8 divisors (see below), whose sum is σ = 22238664. Its totient is φ = 20062080.

The previous prime is 21136319. The next prime is 21136369. The reversal of 21136361 is 16363112.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 8886361 + 12250000 = 2981^2 + 3500^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21136361 - 2¹⁰ = 21135337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21136369) 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 in 7 ways as a sum of consecutive naturals, for example, 5450 + ... + 8483.

It is an arithmetic number, because the mean of its divisors is an integer number (2779833).

Almost surely, 2^21136361 is an apocalyptic number.

It is an amenable number.

21136361 is a deficient number, since it is larger than the sum of its proper divisors (1102303).

21136361 is a wasteful number, since it uses less digits than its factorization.

21136361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14011.

The product of its digits is 648, while the sum is 23.

The square root of 21136361 is about 4597.4298254568. The cubic root of 21136361 is about 276.4882879454.

Adding to 21136361 its reverse (16363112), we get a palindrome (37499473).

It can be divided in two parts, 2 and 1136361, that multiplied together give a palindrome (2272722).

The spelling of 21136361 in words is "twenty-one million, one hundred thirty-six thousand, three hundred sixty-one".