121921 has 2 divisors, whose sum is σ = 121922. Its totient is φ = 121920.
The previous prime is 121909. The next prime is 121931. The reversal of 121921 is 129121.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 112896 + 9025 = 336^2 + 95^2 .
It is an emirp because it is prime and its reverse (129121) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 121921 - 25 = 121889 is a prime.
It is a junction number, because it is equal to n+sod(n) for n = 121895 and 121904.
It is not a weakly prime, because it can be changed into another prime (121931) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60960 + 60961.
It is an arithmetic number, because the mean of its divisors is an integer number (60961).
2121921 is an apocalyptic number.
It is an amenable number.
121921 is a deficient number, since it is larger than the sum of its proper divisors (1).
121921 is an equidigital number, since it uses as much as digits as its factorization.
121921 is an evil number, because the sum of its binary digits is even.
The product of its digits is 36, while the sum is 16.
The square root of 121921 is about 349.1718774472. The cubic root of 121921 is about 49.5860490160.
The spelling of 121921 in words is "one hundred twenty-one thousand, nine hundred twenty-one".
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