21214115261 has 4 divisors (see below), whose sum is σ = 22462004412. Its totient is φ = 19966226112.

The previous prime is 21214115161. The next prime is 21214115267. The reversal of 21214115261 is 16251141212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11731056100 + 9483059161 = 108310^2 + 97381^2 .

It is a cyclic number.

It is not a de Polignac number, because 21214115261 - 2¹⁰ = 21214114237 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21214115261.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21214115267) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 623944550 + ... + 623944583.

It is an arithmetic number, because the mean of its divisors is an integer number (5615501103).

Almost surely, 2^21214115261 is an apocalyptic number.

It is an amenable number.

21214115261 is a deficient number, since it is larger than the sum of its proper divisors (1247889151).

21214115261 is a wasteful number, since it uses less digits than its factorization.

21214115261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1247889150.

The product of its digits is 960, while the sum is 26.

Adding to 21214115261 its reverse (16251141212), we get a palindrome (37465256473).

The spelling of 21214115261 in words is "twenty-one billion, two hundred fourteen million, one hundred fifteen thousand, two hundred sixty-one".