202120921 has 2 divisors, whose sum is σ = 202120922. Its totient is φ = 202120920.

The previous prime is 202120913. The next prime is 202120927. The reversal of 202120921 is 129021202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 172265625 + 29855296 = 13125^2 + 5464^2 .

It is a cyclic number.

It is not a de Polignac number, because 202120921 - 2³ = 202120913 is a prime.

It is not a weakly prime, because it can be changed into another prime (202120927) 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, 101060460 + 101060461.

It is an arithmetic number, because the mean of its divisors is an integer number (101060461).

Almost surely, 2^202120921 is an apocalyptic number.

It is an amenable number.

202120921 is a deficient number, since it is larger than the sum of its proper divisors (1).

202120921 is an equidigital number, since it uses as much as digits as its factorization.

202120921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 202120921 is about 14216.9237530487. The cubic root of 202120921 is about 586.8634866405.

The spelling of 202120921 in words is "two hundred two million, one hundred twenty thousand, nine hundred twenty-one".