851475221 has 2 divisors, whose sum is σ = 851475222. Its totient is φ = 851475220.

The previous prime is 851475187. The next prime is 851475269. The reversal of 851475221 is 122574158.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 819676900 + 31798321 = 28630^2 + 5639^2 .

It is a cyclic number.

It is not a de Polignac number, because 851475221 - 2²⁶ = 784366357 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is equal to p_43653644 and since 851475221 and 43653644 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (851475721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 425737610 + 425737611.

It is an arithmetic number, because the mean of its divisors is an integer number (425737611).

Almost surely, 2^851475221 is an apocalyptic number.

It is an amenable number.

851475221 is a deficient number, since it is larger than the sum of its proper divisors (1).

851475221 is an equidigital number, since it uses as much as digits as its factorization.

851475221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22400, while the sum is 35.

The square root of 851475221 is about 29180.0483378626. The cubic root of 851475221 is about 947.8159322197.

The spelling of 851475221 in words is "eight hundred fifty-one million, four hundred seventy-five thousand, two hundred twenty-one".