1821020122121 has 6 divisors (see below), whose sum is σ = 1934440060830. Its totient is φ = 1713901291136.

The previous prime is 1821020122111. The next prime is 1821020122151. The reversal of 1821020122121 is 1212210201281.

It can be written as a sum of positive squares in 3 ways, for example, as 721583990521 + 1099436131600 = 849461^2 + 1048540^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1821020122121 is a prime.

It is a super-2 number, since 2×1821020122121² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1821020122111) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3150553556 + ... + 3150554133.

It is an arithmetic number, because the mean of its divisors is an integer number (322406676805).

Almost surely, 2^{1821020122121} is an apocalyptic number.

It is an amenable number.

1821020122121 is a deficient number, since it is larger than the sum of its proper divisors (113419938709).

1821020122121 is an equidigital number, since it uses as much as digits as its factorization.

1821020122121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6301107723 (or 6301107706 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 23.

The spelling of 1821020122121 in words is "one trillion, eight hundred twenty-one billion, twenty million, one hundred twenty-two thousand, one hundred twenty-one".