991300602215681 has 4 divisors (see below), whose sum is σ = 1023278040996864. Its totient is φ = 959323163434500.

The previous prime is 991300602215611. The next prime is 991300602215699. The reversal of 991300602215681 is 186512206003199.

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 a de Polignac number, because none of the positive numbers 2^k-991300602215681 is a prime.

It is a super-2 number, since 2×991300602215681² (a number of 31 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991300602215611) 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, 15988719390545 + ... + 15988719390606.

It is an arithmetic number, because the mean of its divisors is an integer number (255819510249216).

Almost surely, 2^{991300602215681} is an apocalyptic number.

It is an amenable number.

991300602215681 is a deficient number, since it is larger than the sum of its proper divisors (31977438781183).

991300602215681 is a wasteful number, since it uses less digits than its factorization.

991300602215681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31977438781182.

The product of its (nonzero) digits is 1399680, while the sum is 53.

The spelling of 991300602215681 in words is "nine hundred ninety-one trillion, three hundred billion, six hundred two million, two hundred fifteen thousand, six hundred eighty-one".