121638613 has 2 divisors, whose sum is σ = 121638614. Its totient is φ = 121638612.

The previous prime is 121638611. The next prime is 121638623. The reversal of 121638613 is 316836121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 120604324 + 1034289 = 10982^2 + 1017^2 .

It is a cyclic number.

It is not a de Polignac number, because 121638613 - 2¹ = 121638611 is a prime.

Together with 121638611, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121638611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60819306 + 60819307.

It is an arithmetic number, because the mean of its divisors is an integer number (60819307).

Almost surely, 2^121638613 is an apocalyptic number.

It is an amenable number.

121638613 is a deficient number, since it is larger than the sum of its proper divisors (1).

121638613 is an equidigital number, since it uses as much as digits as its factorization.

121638613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 31.

The square root of 121638613 is about 11028.9896636093. The cubic root of 121638613 is about 495.4773655648.

The spelling of 121638613 in words is "one hundred twenty-one million, six hundred thirty-eight thousand, six hundred thirteen".