121810421 has 2 divisors, whose sum is σ = 121810422. Its totient is φ = 121810420.

The previous prime is 121810393. The next prime is 121810427. The reversal of 121810421 is 124018121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 108451396 + 13359025 = 10414^2 + 3655^2 .

It is an emirp because it is prime and its reverse (124018121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121810421 - 2¹⁰ = 121809397 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 121810393 and 121810402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121810427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60905210 + 60905211.

It is an arithmetic number, because the mean of its divisors is an integer number (60905211).

Almost surely, 2^121810421 is an apocalyptic number.

It is an amenable number.

121810421 is a deficient number, since it is larger than the sum of its proper divisors (1).

121810421 is an equidigital number, since it uses as much as digits as its factorization.

121810421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 121810421 is about 11036.7758426091. The cubic root of 121810421 is about 495.7105341984.

Adding to 121810421 its reverse (124018121), we get a palindrome (245828542).

The spelling of 121810421 in words is "one hundred twenty-one million, eight hundred ten thousand, four hundred twenty-one".