851057621 has 4 divisors (see below), whose sum is σ = 901119852. Its totient is φ = 800995392.

The previous prime is 851057611. The next prime is 851057639. The reversal of 851057621 is 126750158.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 537590596 + 313467025 = 23186^2 + 17705^2 .

It is a de Polignac number, because none of the positive numbers 2^k-851057621 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (851057611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25031090 + ... + 25031123.

It is an arithmetic number, because the mean of its divisors is an integer number (225279963).

Almost surely, 2^851057621 is an apocalyptic number.

It is an amenable number.

851057621 is a deficient number, since it is larger than the sum of its proper divisors (50062231).

851057621 is a wasteful number, since it uses less digits than its factorization.

851057621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50062230.

The product of its (nonzero) digits is 16800, while the sum is 35.

The square root of 851057621 is about 29172.8918861329. The cubic root of 851057621 is about 947.6609570080.

The spelling of 851057621 in words is "eight hundred fifty-one million, fifty-seven thousand, six hundred twenty-one".