1211221201000 has 64 divisors (see below), whose sum is σ = 2837754279360. Its totient is φ = 483890760000.

The previous prime is 1211221200989. The next prime is 1211221201009. The reversal of 1211221201000 is 1021221121.

It is not an unprimeable number, because it can be changed into a prime (1211221201009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64255 + ... + 1557745.

It is an arithmetic number, because the mean of its divisors is an integer number (44339910615).

Almost surely, 2^{1211221201000} is an apocalyptic number.

1211221201000 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 1211221201000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1418877139680).

1211221201000 is an abundant number, since it is smaller than the sum of its proper divisors (1626533078360).

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

1211221201000 is a wasteful number, since it uses less digits than its factorization.

1211221201000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1494323 (or 1494309 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 1211221201000 its reverse (1021221121), we get a palindrome (1212242422121).

The spelling of 1211221201000 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, two hundred one thousand".