851036221 has 16 divisors (see below), whose sum is σ = 997492608. Its totient is φ = 710841600.

The previous prime is 851036189. The next prime is 851036243. The reversal of 851036221 is 122630158.

851036221 = T₁ + T₂ + ... + T₁₇₂₁.

851036221 is a nontrivial binomial coefficient, being equal to C(1723, 3).

It is not a de Polignac number, because 851036221 - 2⁵ = 851036189 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 851036221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (851036281) by changing a digit.

It is the 1721-st tetrahedral number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 493066 + ... + 494788.

It is an arithmetic number, because the mean of its divisors is an integer number (62343288).

Almost surely, 2^851036221 is an apocalyptic number.

It is an amenable number.

851036221 is a deficient number, since it is larger than the sum of its proper divisors (146456387).

851036221 is a wasteful number, since it uses less digits than its factorization.

851036221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3492.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 851036221 is about 29172.5251049682. The cubic root of 851036221 is about 947.6530139052.

Adding to 851036221 its reverse (122630158), we get a palindrome (973666379).

The spelling of 851036221 in words is "eight hundred fifty-one million, thirty-six thousand, two hundred twenty-one".