1211551500000 has 336 divisors, whose sum is σ = 4040827339248. Its totient is φ = 317760000000.

The previous prime is 1211551499971. The next prime is 1211551500001. The reversal of 1211551500000 is 51551121.

It is a self number, because there is not a number n which added to its sum of digits gives 1211551500000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211551500001) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 91493380 + ... + 91506620.

It is an arithmetic number, because the mean of its divisors is an integer number (12026271843).

Almost surely, 2^{1211551500000} is an apocalyptic number.

1211551500000 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 1211551500000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2020413669624).

1211551500000 is an abundant number, since it is smaller than the sum of its proper divisors (2829275839248).

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

1211551500000 is an frugal number, since it uses more digits than its factorization.

1211551500000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13345 (or 13312 counting only the distinct ones).

The product of its (nonzero) digits is 250, while the sum is 21.

The spelling of 1211551500000 in words is "one trillion, two hundred eleven billion, five hundred fifty-one million, five hundred thousand".