851221965 has 16 divisors (see below), whose sum is σ = 1485769536. Its totient is φ = 412713600.

The previous prime is 851221873. The next prime is 851221981. The reversal of 851221965 is 569122158.

It is not a de Polignac number, because 851221965 - 2⁷ = 851221837 is a prime.

It is a super-2 number, since 2×851221965² = 1449157667396922450, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2579296 + ... + 2579625.

It is an arithmetic number, because the mean of its divisors is an integer number (92860596).

Almost surely, 2^851221965 is an apocalyptic number.

It is an amenable number.

851221965 is a deficient number, since it is larger than the sum of its proper divisors (634547571).

851221965 is a wasteful number, since it uses less digits than its factorization.

851221965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5158940.

The product of its digits is 43200, while the sum is 39.

The square root of 851221965 is about 29175.7084746883. The cubic root of 851221965 is about 947.7219526306.

The spelling of 851221965 in words is "eight hundred fifty-one million, two hundred twenty-one thousand, nine hundred sixty-five".