651591 has 8 divisors (see below), whose sum is σ = 965360. Its totient is φ = 434376.

The previous prime is 651587. The next prime is 651617. The reversal of 651591 is 195156.

651591 is a `hidden beast` number, since 651 + 5 + 9 + 1 = 666.

It is not a de Polignac number, because 651591 - 2² = 651587 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 24133 = 651591 / (6 + 5 + 1 + 5 + 9 + 1).

It is a Duffinian number.

651591 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12040 + ... + 12093.

It is an arithmetic number, because the mean of its divisors is an integer number (120670).

2⁶⁵¹⁵⁹¹ is an apocalyptic number.

651591 is a deficient number, since it is larger than the sum of its proper divisors (313769).

651591 is a wasteful number, since it uses less digits than its factorization.

651591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24142 (or 24136 counting only the distinct ones).

The product of its digits is 1350, while the sum is 27.

The square root of 651591 is about 807.2118680991. The cubic root of 651591 is about 86.6945291743.

The spelling of 651591 in words is "six hundred fifty-one thousand, five hundred ninety-one".