1221020100023 has 4 divisors (see below), whose sum is σ = 1223934229560. Its totient is φ = 1218105970488.

The previous prime is 1221020099993. The next prime is 1221020100037. The reversal of 1221020100023 is 3200010201221.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1221020100023 - 2¹⁴ = 1221020083639 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221020099980 and 1221020100007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221020102023) 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, 1457064140 + ... + 1457064977.

It is an arithmetic number, because the mean of its divisors is an integer number (305983557390).

Almost surely, 2^{1221020100023} is an apocalyptic number.

1221020100023 is a deficient number, since it is larger than the sum of its proper divisors (2914129537).

1221020100023 is an equidigital number, since it uses as much as digits as its factorization.

1221020100023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2914129536.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 1221020100023 its reverse (3200010201221), we get a palindrome (4421030301244).

The spelling of 1221020100023 in words is "one trillion, two hundred twenty-one billion, twenty million, one hundred thousand, twenty-three".