1221100102121 has 16 divisors (see below), whose sum is σ = 1254091722576. Its totient is φ = 1188540000000.

The previous prime is 1221100102111. The next prime is 1221100102127. The reversal of 1221100102121 is 1212010011221.

It can be written as a sum of positive squares in 8 ways, for example, as 1818169600 + 1219281932521 = 42640^2 + 1104211^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221100102121 - 2²² = 1221095907817 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221100102096 and 1221100102105.

It is not an unprimeable number, because it can be changed into a prime (1221100102127) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11412371 + ... + 11518871.

It is an arithmetic number, because the mean of its divisors is an integer number (78380732661).

Almost surely, 2^{1221100102121} is an apocalyptic number.

It is an amenable number.

1221100102121 is a deficient number, since it is larger than the sum of its proper divisors (32991620455).

1221100102121 is a wasteful number, since it uses less digits than its factorization.

1221100102121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108524.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 1221100102121 its reverse (1212010011221), we get a palindrome (2433110113342).

The spelling of 1221100102121 in words is "one trillion, two hundred twenty-one billion, one hundred million, one hundred two thousand, one hundred twenty-one".