9999865381 has 4 divisors (see below), whose sum is σ = 10908944064. Its totient is φ = 9090786700.

The previous prime is 9999865339. The next prime is 9999865391. The reversal of 9999865381 is 1835689999.

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 9999865381 - 2¹⁷ = 9999734309 is a prime.

It is a super-2 number, since 2×9999865381² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9999865391) 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, 454539325 + ... + 454539346.

It is an arithmetic number, because the mean of its divisors is an integer number (2727236016).

Almost surely, 2^9999865381 is an apocalyptic number.

It is an amenable number.

9999865381 is a deficient number, since it is larger than the sum of its proper divisors (909078683).

9999865381 is a wasteful number, since it uses less digits than its factorization.

9999865381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909078682.

The product of its digits is 37791360, while the sum is 67.

The square root of 9999865381 is about 99999.3269027347. The cubic root of 9999865381 is about 2154.4250223937.

The spelling of 9999865381 in words is "nine billion, nine hundred ninety-nine million, eight hundred sixty-five thousand, three hundred eighty-one".