201231210121 has 8 divisors (see below), whose sum is σ = 202525466184. Its totient is φ = 199937112960.

The previous prime is 201231210109. The next prime is 201231210133. The reversal of 201231210121 is 121012132102.

It is an interprime number because it is at equal distance from previous prime (201231210109) and next prime (201231210133).

It can be written as a sum of positive squares in 4 ways, for example, as 12731962896 + 188499247225 = 112836^2 + 434165^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201231210121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 201231210095 and 201231210104.

It is not an unprimeable number, because it can be changed into a prime (201231210181) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3521901 + ... + 3578581.

It is an arithmetic number, because the mean of its divisors is an integer number (25315683273).

Almost surely, 2^201231210121 is an apocalyptic number.

It is an amenable number.

201231210121 is a deficient number, since it is larger than the sum of its proper divisors (1294256063).

201231210121 is a wasteful number, since it uses less digits than its factorization.

201231210121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79451.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 201231210121 its reverse (121012132102), we get a palindrome (322243342223).

The spelling of 201231210121 in words is "two hundred one billion, two hundred thirty-one million, two hundred ten thousand, one hundred twenty-one".