1291986198 has 24 divisors (see below), whose sum is σ = 2802327528. Its totient is φ = 430196832.

The previous prime is 1291986191. The next prime is 1291986203. The reversal of 1291986198 is 8916891921.

1291986198 is a `hidden beast` number, since 1 + 2 + 9 + 19 + 8 + 619 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291986191) 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 11 ways as a sum of consecutive naturals, for example, 21436 + ... + 55167.

It is an arithmetic number, because the mean of its divisors is an integer number (116763647).

Almost surely, 2^1291986198 is an apocalyptic number.

1291986198 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1291986198 is an abundant number, since it is smaller than the sum of its proper divisors (1510341330).

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

1291986198 is a wasteful number, since it uses less digits than its factorization.

1291986198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77548 (or 77545 counting only the distinct ones).

The product of its digits is 559872, while the sum is 54.

The square root of 1291986198 is about 35944.2095197544. The cubic root of 1291986198 is about 1089.1456419943.

The spelling of 1291986198 in words is "one billion, two hundred ninety-one million, nine hundred eighty-six thousand, one hundred ninety-eight".