21166013245 has 8 divisors (see below), whose sum is σ = 27353001816. Its totient is φ = 15630286656.

The previous prime is 21166013179. The next prime is 21166013261. The reversal of 21166013245 is 54231066112.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1972958724 + 19193054521 = 44418^2 + 138539^2 .

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 21166013245 - 2⁷ = 21166013117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 162815422 + ... + 162815551.

It is an arithmetic number, because the mean of its divisors is an integer number (3419125227).

Almost surely, 2^21166013245 is an apocalyptic number.

It is an amenable number.

21166013245 is a deficient number, since it is larger than the sum of its proper divisors (6186988571).

21166013245 is a wasteful number, since it uses less digits than its factorization.

21166013245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325630991.

The product of its (nonzero) digits is 8640, while the sum is 31.

Adding to 21166013245 its reverse (54231066112), we get a palindrome (75397079357).

The spelling of 21166013245 in words is "twenty-one billion, one hundred sixty-six million, thirteen thousand, two hundred forty-five".