805649 has 8 divisors (see below), whose sum is σ = 897960. Its totient is φ = 717696.

The previous prime is 805639. The next prime is 805687. The reversal of 805649 is 946508.

It can be written as a sum of positive squares in 4 ways, for example, as 4624 + 801025 = 68^2 + 895^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 805649 - 2⁴ = 805633 is a prime.

It is a super-2 number, since 2×805649² = 1298140622402, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (805639) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 692 + ... + 1445.

It is an arithmetic number, because the mean of its divisors is an integer number (112245).

2⁸⁰⁵⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

805649 is a deficient number, since it is larger than the sum of its proper divisors (92311).

805649 is a wasteful number, since it uses less digits than its factorization.

805649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2179.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 805649 is about 897.5795229393. The cubic root of 805649 is about 93.0497671738.

The spelling of 805649 in words is "eight hundred five thousand, six hundred forty-nine".