646469 has 4 divisors (see below), whose sum is σ = 648396. Its totient is φ = 644544.

The previous prime is 646453. The next prime is 646519. The reversal of 646469 is 964646.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 964646 = 2 ⋅482323.

It can be written as a sum of positive squares in 2 ways, for example, as 315844 + 330625 = 562^2 + 575^2 .

It is a cyclic number.

It is not a de Polignac number, because 646469 - 2⁴ = 646453 is a prime.

It is a super-2 number, since 2×646469² = 835844335922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646169) 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, 314 + ... + 1179.

It is an arithmetic number, because the mean of its divisors is an integer number (162099).

2⁶⁴⁶⁴⁶⁹ is an apocalyptic number.

It is an amenable number.

646469 is a deficient number, since it is larger than the sum of its proper divisors (1927).

646469 is a wasteful number, since it uses less digits than its factorization.

646469 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1926.

The product of its digits is 31104, while the sum is 35.

The square root of 646469 is about 804.0329595234. The cubic root of 646469 is about 86.4667697321.

The spelling of 646469 in words is "six hundred forty-six thousand, four hundred sixty-nine".