651605 has 10 divisors (see below), whose sum is σ = 825366. Its totient is φ = 493848.

The previous prime is 651587. The next prime is 651617. The reversal of 651605 is 506156.

It can be written as a sum of positive squares in only one way, i.e., 521284 + 130321 = 722^2 + 361^2 .

It is not a de Polignac number, because 651605 - 2¹⁰ = 650581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 9 ways as a sum of consecutive naturals, for example, 34286 + ... + 34304.

2⁶⁵¹⁶⁰⁵ is an apocalyptic number.

It is an amenable number.

651605 is a deficient number, since it is larger than the sum of its proper divisors (173761).

651605 is an frugal number, since it uses more digits than its factorization.

651605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81 (or 24 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 651605 is about 807.2205398774. The cubic root of 651605 is about 86.6951500724.

The spelling of 651605 in words is "six hundred fifty-one thousand, six hundred five".