1221000231131 has 4 divisors (see below), whose sum is σ = 1221039939552. Its totient is φ = 1220960522712.

The previous prime is 1221000231109. The next prime is 1221000231233. The reversal of 1221000231131 is 1311320001221.

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 1221000231131 - 2²⁶ = 1220933122267 is a prime.

It is a super-2 number, since 2×1221000231131² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221000237131) 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, 19808051 + ... + 19869596.

It is an arithmetic number, because the mean of its divisors is an integer number (305259984888).

Almost surely, 2^{1221000231131} is an apocalyptic number.

1221000231131 is a deficient number, since it is larger than the sum of its proper divisors (39708421).

1221000231131 is an equidigital number, since it uses as much as digits as its factorization.

1221000231131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39708420.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 1221000231131 its reverse (1311320001221), we get a palindrome (2532320232352).

The spelling of 1221000231131 in words is "one trillion, two hundred twenty-one billion, two hundred thirty-one thousand, one hundred thirty-one".