12691998 has 64 divisors (see below), whose sum is σ = 32140800. Its totient is φ = 3674880.

The previous prime is 12691997. The next prime is 12692027. The reversal of 12691998 is 89919621.

It is a super-2 number, since 2×12691998² = 322173626464008, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12691997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13198 + ... + 14126.

It is an arithmetic number, because the mean of its divisors is an integer number (502200).

Almost surely, 2^12691998 is an apocalyptic number.

12691998 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 12691998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16070400).

12691998 is an abundant number, since it is smaller than the sum of its proper divisors (19448802).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12691998 is a wasteful number, since it uses less digits than its factorization.

12691998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 974 (or 968 counting only the distinct ones).

The product of its digits is 69984, while the sum is 45.

The square root of 12691998 is about 3562.5830516635. The cubic root of 12691998 is about 233.2616437359.

It can be divided in two parts, 12691 and 998, that added together give a square (13689 = 117²).

The spelling of 12691998 in words is "twelve million, six hundred ninety-one thousand, nine hundred ninety-eight".