1221011101020 has 48 divisors (see below), whose sum is σ = 3418943881248. Its totient is φ = 325592217600.

The previous prime is 1221011101003. The next prime is 1221011101171. The reversal of 1221011101020 is 201011101221.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 1221011100987 and 1221011101005.

It is a congruent number.

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, 1589220 + ... + 2228820.

It is an arithmetic number, because the mean of its divisors is an integer number (71227997526).

Almost surely, 2^{1221011101020} is an apocalyptic number.

1221011101020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221011101020 is an abundant number, since it is smaller than the sum of its proper divisors (2197932780228).

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

1221011101020 is a wasteful number, since it uses less digits than its factorization.

1221011101020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 671430 (or 671428 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 1221011101020 its reverse (201011101221), we get a palindrome (1422022202241).

The spelling of 1221011101020 in words is "one trillion, two hundred twenty-one billion, eleven million, one hundred one thousand, twenty".