902181221 has 2 divisors, whose sum is σ = 902181222. Its totient is φ = 902181220.

The previous prime is 902181209. The next prime is 902181227. The reversal of 902181221 is 122181209.

902181221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 649689121 + 252492100 = 25489^2 + 15890^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-902181221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (902181227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 451090610 + 451090611.

It is an arithmetic number, because the mean of its divisors is an integer number (451090611).

Almost surely, 2^902181221 is an apocalyptic number.

It is an amenable number.

902181221 is a deficient number, since it is larger than the sum of its proper divisors (1).

902181221 is an equidigital number, since it uses as much as digits as its factorization.

902181221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 902181221 is about 30036.3316834796. The cubic root of 902181221 is about 966.2687352351.

The spelling of 902181221 in words is "nine hundred two million, one hundred eighty-one thousand, two hundred twenty-one".