1220121001021 has 4 divisors (see below), whose sum is σ = 1313976462652. Its totient is φ = 1126265539392.

The previous prime is 1220121000937. The next prime is 1220121001061. The reversal of 1220121001021 is 1201001210221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 653429722500 + 566691278521 = 808350^2 + 752789^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220121001021 - 2²⁹ = 1219584130109 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 93855461617 = 1220121001021 / (1 + 2 + 2 + 0 + 1 + 2 + 1 + 0 + 0 + 1 + 0 + 2 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1220121000992 and 1220121001010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220121001061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46927730796 + ... + 46927730821.

It is an arithmetic number, because the mean of its divisors is an integer number (328494115663).

Almost surely, 2^{1220121001021} is an apocalyptic number.

It is an amenable number.

1220121001021 is a deficient number, since it is larger than the sum of its proper divisors (93855461631).

1220121001021 is an equidigital number, since it uses as much as digits as its factorization.

1220121001021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93855461630.

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

Adding to 1220121001021 its reverse (1201001210221), we get a palindrome (2421122211242).

The spelling of 1220121001021 in words is "one trillion, two hundred twenty billion, one hundred twenty-one million, one thousand, twenty-one".