1211221111020 has 48 divisors (see below), whose sum is σ = 3391598370048. Its totient is φ = 322975224000.

The previous prime is 1211221110919. The next prime is 1211221111049. The reversal of 1211221111020 is 201111221121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 632145 + ... + 1679895.

It is an arithmetic number, because the mean of its divisors is an integer number (70658299376).

Almost surely, 2^{1211221111020} is an apocalyptic number.

1211221111020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211221111020 is an abundant number, since it is smaller than the sum of its proper divisors (2180377259028).

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

1211221111020 is a wasteful number, since it uses less digits than its factorization.

1211221111020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067030 (or 1067028 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1211221111020 its reverse (201111221121), we get a palindrome (1412332332141).

The spelling of 1211221111020 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, one hundred eleven thousand, twenty".