121531021 has 2 divisors, whose sum is σ = 121531022. Its totient is φ = 121531020.

The previous prime is 121531019. The next prime is 121531037. The reversal of 121531021 is 120135121.

It is an a-pointer prime, because the next prime (121531037) can be obtained adding 121531021 to its sum of digits (16).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 93334921 + 28196100 = 9661^2 + 5310^2 .

It is an emirp because it is prime and its reverse (120135121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121531021 - 2¹ = 121531019 is a prime.

Together with 121531019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 121530986 and 121531004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121531001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60765510 + 60765511.

It is an arithmetic number, because the mean of its divisors is an integer number (60765511).

Almost surely, 2^121531021 is an apocalyptic number.

It is an amenable number.

121531021 is a deficient number, since it is larger than the sum of its proper divisors (1).

121531021 is an equidigital number, since it uses as much as digits as its factorization.

121531021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60, while the sum is 16.

The square root of 121531021 is about 11024.1108938544. The cubic root of 121531021 is about 495.3312356342.

Adding to 121531021 its reverse (120135121), we get a palindrome (241666142).

The spelling of 121531021 in words is "one hundred twenty-one million, five hundred thirty-one thousand, twenty-one".