9999863801565 has 128 divisors (see below), whose sum is σ = 19458280857600. Its totient is φ = 4322034339840.

The previous prime is 9999863801563. The next prime is 9999863801581. The reversal of 9999863801565 is 5651083689999.

9999863801565 is a nontrivial binomial coefficient, being equal to C(4472106, 2).

It is not a de Polignac number, because 9999863801565 - 2¹ = 9999863801563 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9999863801563) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 254890371 + ... + 254929599.

It is an arithmetic number, because the mean of its divisors is an integer number (152017819200).

Almost surely, 2^{9999863801565} is an apocalyptic number.

9999863801565 is a gapful number since it is divisible by the number (95) formed by its first and last digit.

9999863801565 is the 4472105-th triangular number and also the 2236053-rd hexagonal number.

It is an amenable number.

9999863801565 is a deficient number, since it is larger than the sum of its proper divisors (9458417056035).

9999863801565 is a wasteful number, since it uses less digits than its factorization.

9999863801565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44067.

The product of its (nonzero) digits is 1133740800, while the sum is 78.

The spelling of 9999863801565 in words is "nine trillion, nine hundred ninety-nine billion, eight hundred sixty-three million, eight hundred one thousand, five hundred sixty-five".