1221001011020 has 36 divisors (see below), whose sum is σ = 2982731043600. Its totient is φ = 418628917728.

The previous prime is 1221001010969. The next prime is 1221001011023. The reversal of 1221001011020 is 201101001221.

It is a super-2 number, since 2×1221001011020² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221001010992 and 1221001011010.

It is not an unprimeable number, because it can be changed into a prime (1221001011023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 622958720 + ... + 622960679.

It is an arithmetic number, because the mean of its divisors is an integer number (82853640100).

Almost surely, 2^{1221001011020} is an apocalyptic number.

1221001011020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221001011020 is an abundant number, since it is smaller than the sum of its proper divisors (1761730032580).

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

1221001011020 is a wasteful number, since it uses less digits than its factorization.

1221001011020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1245919422 (or 1245919413 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 1221001011020 its reverse (201101001221), we get a palindrome (1422102012241).

The spelling of 1221001011020 in words is "one trillion, two hundred twenty-one billion, one million, eleven thousand, twenty".