2121121212157 has 2 divisors, whose sum is σ = 2121121212158. Its totient is φ = 2121121212156.

The previous prime is 2121121212139. The next prime is 2121121212193. The reversal of 2121121212157 is 7512121211212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1787090386041 + 334030826116 = 1336821^2 + 577954^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2121121212157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2121121212137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060560606078 + 1060560606079.

It is an arithmetic number, because the mean of its divisors is an integer number (1060560606079).

Almost surely, 2^{2121121212157} is an apocalyptic number.

It is an amenable number.

2121121212157 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121121212157 is an equidigital number, since it uses as much as digits as its factorization.

2121121212157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1120, while the sum is 28.

Adding to 2121121212157 its reverse (7512121211212), we get a palindrome (9633242423369).

The spelling of 2121121212157 in words is "two trillion, one hundred twenty-one billion, one hundred twenty-one million, two hundred twelve thousand, one hundred fifty-seven".