21516842965 has 8 divisors (see below), whose sum is σ = 27339047640. Its totient is φ = 16200916992.

The previous prime is 21516842959. The next prime is 21516842983. The reversal of 21516842965 is 56924861512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 8958054609 + 12558788356 = 94647^2 + 112066^2 .

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 21516842965 - 2⁹ = 21516842453 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126569580 + ... + 126569749.

It is an arithmetic number, because the mean of its divisors is an integer number (3417380955).

Almost surely, 2^21516842965 is an apocalyptic number.

It is an amenable number.

21516842965 is a deficient number, since it is larger than the sum of its proper divisors (5822204675).

21516842965 is a wasteful number, since it uses less digits than its factorization.

21516842965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253139351.

The product of its digits is 1036800, while the sum is 49.

The spelling of 21516842965 in words is "twenty-one billion, five hundred sixteen million, eight hundred forty-two thousand, nine hundred sixty-five".