1231500002121 has 6 divisors (see below), whose sum is σ = 1778833336410. Its totient is φ = 821000001408.

The previous prime is 1231500002101. The next prime is 1231500002177. The reversal of 1231500002121 is 1212000051321.

1231500002121 is a `hidden beast` number, since 12 + 31 + 500 + 0 + 0 + 2 + 121 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1008144516096 + 223355486025 = 1004064^2 + 472605^2 .

It is not a de Polignac number, because 1231500002121 - 2⁹ = 1231500001609 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1231500002094 and 1231500002103.

It is not an unprimeable number, because it can be changed into a prime (1231500002101) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 68416666776 + ... + 68416666793.

It is an arithmetic number, because the mean of its divisors is an integer number (296472222735).

Almost surely, 2^{1231500002121} is an apocalyptic number.

It is an amenable number.

1231500002121 is a deficient number, since it is larger than the sum of its proper divisors (547333334289).

1231500002121 is a wasteful number, since it uses less digits than its factorization.

1231500002121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136833333575 (or 136833333572 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

Adding to 1231500002121 its reverse (1212000051321), we get a palindrome (2443500053442).

The spelling of 1231500002121 in words is "one trillion, two hundred thirty-one billion, five hundred million, two thousand, one hundred twenty-one".