851512621 has 2 divisors, whose sum is σ = 851512622. Its totient is φ = 851512620.

The previous prime is 851512591. The next prime is 851512631. The reversal of 851512621 is 126215158.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 794676100 + 56836521 = 28190^2 + 7539^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-851512621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (851512631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 425756310 + 425756311.

It is an arithmetic number, because the mean of its divisors is an integer number (425756311).

Almost surely, 2^851512621 is an apocalyptic number.

It is an amenable number.

851512621 is a deficient number, since it is larger than the sum of its proper divisors (1).

851512621 is an equidigital number, since it uses as much as digits as its factorization.

851512621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4800, while the sum is 31.

The square root of 851512621 is about 29180.6891796613. The cubic root of 851512621 is about 947.8298092322.

Adding to 851512621 its reverse (126215158), we get a palindrome (977727779).

The spelling of 851512621 in words is "eight hundred fifty-one million, five hundred twelve thousand, six hundred twenty-one".