9917965581 has 4 divisors (see below), whose sum is σ = 13223954112. Its totient is φ = 6611977052.

The previous prime is 9917965571. The next prime is 9917965601. The reversal of 9917965581 is 1855697199.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 9917965581 - 2¹³ = 9917957389 is a prime.

It is a super-2 number, since 2×9917965581² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9917965571) 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, 1652994261 + ... + 1652994266.

It is an arithmetic number, because the mean of its divisors is an integer number (3305988528).

Almost surely, 2^9917965581 is an apocalyptic number.

It is an amenable number.

9917965581 is a deficient number, since it is larger than the sum of its proper divisors (3305988531).

9917965581 is a wasteful number, since it uses less digits than its factorization.

9917965581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3305988530.

The product of its digits is 6123600, while the sum is 60.

The square root of 9917965581 is about 99588.9832310783. The cubic root of 9917965581 is about 2148.5272467374.

The spelling of 9917965581 in words is "nine billion, nine hundred seventeen million, nine hundred sixty-five thousand, five hundred eighty-one".