851744421 has 48 divisors (see below), whose sum is σ = 1434438720. Its totient is φ = 481282560.

The previous prime is 851744359. The next prime is 851744459. The reversal of 851744421 is 124447158.

It is a happy number.

It is not a de Polignac number, because 851744421 - 2¹¹ = 851742373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (851742421) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 181126 + ... + 185768.

It is an arithmetic number, because the mean of its divisors is an integer number (29884140).

Almost surely, 2^851744421 is an apocalyptic number.

It is an amenable number.

851744421 is a deficient number, since it is larger than the sum of its proper divisors (582694299).

851744421 is a wasteful number, since it uses less digits than its factorization.

851744421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4786 (or 4783 counting only the distinct ones).

The product of its digits is 35840, while the sum is 36.

The square root of 851744421 is about 29184.6607141491. The cubic root of 851744421 is about 947.9158079640.

It can be divided in two parts, 851744 and 421, that added together give a triangular number (852165 = T₁₃₀₅).

The spelling of 851744421 in words is "eight hundred fifty-one million, seven hundred forty-four thousand, four hundred twenty-one".