10661220121 has 4 divisors (see below), whose sum is σ = 10661438592. Its totient is φ = 10661001652.

The previous prime is 10661220113. The next prime is 10661220133. The reversal of 10661220121 is 12102216601.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12102216601 = 1627 ⋅7438363.

It is a cyclic number.

It is not a de Polignac number, because 10661220121 - 2³ = 10661220113 is a prime.

It is a super-2 number, since 2×10661220121² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 10661220092 and 10661220101.

It is not an unprimeable number, because it can be changed into a prime (10661223121) 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, 1140 + ... + 146026.

It is an arithmetic number, because the mean of its divisors is an integer number (2665359648).

Almost surely, 2^10661220121 is an apocalyptic number.

It is an amenable number.

10661220121 is a deficient number, since it is larger than the sum of its proper divisors (218471).

10661220121 is an equidigital number, since it uses as much as digits as its factorization.

10661220121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218470.

The product of its (nonzero) digits is 288, while the sum is 22.

Adding to 10661220121 its reverse (12102216601), we get a palindrome (22763436722).

The spelling of 10661220121 in words is "ten billion, six hundred sixty-one million, two hundred twenty thousand, one hundred twenty-one".