12891998440 has 32 divisors (see below), whose sum is σ = 29010446280. Its totient is φ = 5156186112.

The previous prime is 12891998437. The next prime is 12891998443. The reversal of 12891998440 is 4489919821.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (12891998437) and next prime (12891998443).

It can be written as a sum of positive squares in 4 ways, for example, as 11784839364 + 1107159076 = 108558^2 + 33274^2 .

It is a Smith number, since the sum of its digits (55) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (12891998443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 485344 + ... + 511216.

Almost surely, 2^12891998440 is an apocalyptic number.

12891998440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12891998440 is an abundant number, since it is smaller than the sum of its proper divisors (16118447840).

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

12891998440 is a wasteful number, since it uses less digits than its factorization.

12891998440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38341 (or 38337 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 55.

The spelling of 12891998440 in words is "twelve billion, eight hundred ninety-one million, nine hundred ninety-eight thousand, four hundred forty".