1221100023 has 16 divisors (see below), whose sum is σ = 1912772736. Its totient is φ = 683132640.

The previous prime is 1221099967. The next prime is 1221100033. The reversal of 1221100023 is 3200011221.

It is not a de Polignac number, because 1221100023 - 2¹⁸ = 1220837879 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221099981 and 1221100008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221100033) 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, 1422765 + ... + 1423622.

It is an arithmetic number, because the mean of its divisors is an integer number (119548296).

Almost surely, 2^1221100023 is an apocalyptic number.

1221100023 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1221100023 is a deficient number, since it is larger than the sum of its proper divisors (691672713).

1221100023 is a wasteful number, since it uses less digits than its factorization.

1221100023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2846414.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 1221100023 is about 34944.2416286289. The cubic root of 1221100023 is about 1068.8507832047.

Adding to 1221100023 its reverse (3200011221), we get a palindrome (4421111244).

The spelling of 1221100023 in words is "one billion, two hundred twenty-one million, one hundred thousand, twenty-three".