2121111257 has 2 divisors, whose sum is σ = 2121111258. Its totient is φ = 2121111256.

The previous prime is 2121111253. The next prime is 2121111277. The reversal of 2121111257 is 7521111212.

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., 1141358656 + 979752601 = 33784^2 + 31301^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121111257 - 2² = 2121111253 is a prime.

It is a super-2 number, since 2×2121111257² = 8998225929144240098, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2121111253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060555628 + 1060555629.

It is an arithmetic number, because the mean of its divisors is an integer number (1060555629).

Almost surely, 2^2121111257 is an apocalyptic number.

It is an amenable number.

2121111257 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121111257 is an equidigital number, since it uses as much as digits as its factorization.

2121111257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 280, while the sum is 23.

The square root of 2121111257 is about 46055.5236318077. The cubic root of 2121111257 is about 1284.8560769835.

Adding to 2121111257 its reverse (7521111212), we get a palindrome (9642222469).

The spelling of 2121111257 in words is "two billion, one hundred twenty-one million, one hundred eleven thousand, two hundred fifty-seven".