646977 has 4 divisors (see below), whose sum is σ = 862640. Its totient is φ = 431316.

The previous prime is 646957. The next prime is 646979. The reversal of 646977 is 779646.

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.

It is not a de Polignac number, because 646977 - 2⁶ = 646913 is a prime.

It is a D-number.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 646977.

It is not an unprimeable number, because it can be changed into a prime (646979) 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 3 ways as a sum of consecutive naturals, for example, 107827 + ... + 107832.

It is an arithmetic number, because the mean of its divisors is an integer number (215660).

2⁶⁴⁶⁹⁷⁷ is an apocalyptic number.

It is an amenable number.

646977 is a deficient number, since it is larger than the sum of its proper divisors (215663).

646977 is a wasteful number, since it uses less digits than its factorization.

646977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215662.

The product of its digits is 63504, while the sum is 39.

The square root of 646977 is about 804.3488049348. The cubic root of 646977 is about 86.4894125391.

The spelling of 646977 in words is "six hundred forty-six thousand, nine hundred seventy-seven".