851514991 has 4 divisors (see below), whose sum is σ = 852058584. Its totient is φ = 850971400.

The previous prime is 851514971. The next prime is 851515051. The reversal of 851514991 is 199415158.

851514991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199415158 = 2 ⋅99707579.

It is a cyclic number.

It is not a de Polignac number, because 851514991 - 2⁵ = 851514959 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (851514971) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 269440 + ... + 272581.

It is an arithmetic number, because the mean of its divisors is an integer number (213014646).

Almost surely, 2^851514991 is an apocalyptic number.

851514991 is a deficient number, since it is larger than the sum of its proper divisors (543593).

851514991 is a wasteful number, since it uses less digits than its factorization.

851514991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 543592.

The product of its digits is 64800, while the sum is 43.

The square root of 851514991 is about 29180.7297886807. The cubic root of 851514991 is about 947.8306885907.

The spelling of 851514991 in words is "eight hundred fifty-one million, five hundred fourteen thousand, nine hundred ninety-one".