647761 has 4 divisors (see below), whose sum is σ = 658800. Its totient is φ = 636724.

The previous prime is 647753. The next prime is 647771. The reversal of 647761 is 167746.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 167746 = 2 ⋅83873.

It is a cyclic number.

It is not a de Polignac number, because 647761 - 2³ = 647753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (647741) 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, 5431 + ... + 5548.

It is an arithmetic number, because the mean of its divisors is an integer number (164700).

2⁶⁴⁷⁷⁶¹ is an apocalyptic number.

It is an amenable number.

647761 is a deficient number, since it is larger than the sum of its proper divisors (11039).

647761 is a wasteful number, since it uses less digits than its factorization.

647761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11038.

The product of its digits is 7056, while the sum is 31.

The square root of 647761 is about 804.8360081408. The cubic root of 647761 is about 86.5243340939.

The spelling of 647761 in words is "six hundred forty-seven thousand, seven hundred sixty-one".