121637819 has 2 divisors, whose sum is σ = 121637820. Its totient is φ = 121637818.

The previous prime is 121637807. The next prime is 121637821. The reversal of 121637819 is 918736121.

It is a strong prime.

It is an emirp because it is prime and its reverse (918736121) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121637819 is a prime.

It is a super-2 number, since 2×121637819² = 29591518022153522, which contains 22 as substring.

Together with 121637821, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (121637849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60818909 + 60818910.

It is an arithmetic number, because the mean of its divisors is an integer number (60818910).

Almost surely, 2^121637819 is an apocalyptic number.

121637819 is a deficient number, since it is larger than the sum of its proper divisors (1).

121637819 is an equidigital number, since it uses as much as digits as its factorization.

121637819 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 38.

The square root of 121637819 is about 11028.9536675063. The cubic root of 121637819 is about 495.4762874809.

The spelling of 121637819 in words is "one hundred twenty-one million, six hundred thirty-seven thousand, eight hundred nineteen".