811981502997 has 16 divisors (see below), whose sum is σ = 1245499226112. Its totient is φ = 460916650800.

The previous prime is 811981502971. The next prime is 811981503029. The reversal of 811981502997 is 799205189118.

It is not a de Polignac number, because 811981502997 - 2¹⁶ = 811981437461 is a prime.

It is a super-2 number, since 2×811981502997² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 811981502997.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811981502947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 128029233 + ... + 128035574.

It is an arithmetic number, because the mean of its divisors is an integer number (77843701632).

Almost surely, 2^811981502997 is an apocalyptic number.

It is an amenable number.

811981502997 is a deficient number, since it is larger than the sum of its proper divisors (433517723115).

811981502997 is a wasteful number, since it uses less digits than its factorization.

811981502997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256064968.

The product of its (nonzero) digits is 3265920, while the sum is 60.

The spelling of 811981502997 in words is "eight hundred eleven billion, nine hundred eighty-one million, five hundred two thousand, nine hundred ninety-seven".