1271998253240 has 384 divisors, whose sum is σ = 3600970188480. Its totient is φ = 398400921600.

The previous prime is 1271998253221. The next prime is 1271998253287. The reversal of 1271998253240 is 423528991721.

It is a Cunningham number, because it is equal to 1127829²-1.

It is a super-2 number, since 2×1271998253240² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 124055954 + ... + 124066206.

Almost surely, 2^{1271998253240} is an apocalyptic number.

1271998253240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1271998253240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1800485094240).

1271998253240 is an abundant number, since it is smaller than the sum of its proper divisors (2328971935240).

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

1271998253240 is a wasteful number, since it uses less digits than its factorization.

1271998253240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10375 (or 10348 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 53.

The spelling of 1271998253240 in words is "one trillion, two hundred seventy-one billion, nine hundred ninety-eight million, two hundred fifty-three thousand, two hundred forty".