1221110100021 has 64 divisors (see below), whose sum is σ = 1903881254912. Its totient is φ = 681760800000.

The previous prime is 1221110099999. The next prime is 1221110100043. The reversal of 1221110100021 is 1200010111221.

It is an interprime number because it is at equal distance from previous prime (1221110099999) and next prime (1221110100043).

It is not a de Polignac number, because 1221110100021 - 2²¹ = 1221108002869 is a prime.

It is a super-2 number, since 2×1221110100021² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221110100061) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 243683406 + ... + 243688416.

It is an arithmetic number, because the mean of its divisors is an integer number (29748144608).

Almost surely, 2^{1221110100021} is an apocalyptic number.

It is an amenable number.

1221110100021 is a deficient number, since it is larger than the sum of its proper divisors (682771154891).

1221110100021 is a wasteful number, since it uses less digits than its factorization.

1221110100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6314.

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

Adding to 1221110100021 its reverse (1200010111221), we get a palindrome (2421120211242).

The spelling of 1221110100021 in words is "one trillion, two hundred twenty-one billion, one hundred ten million, one hundred thousand, twenty-one".