646123069 has 4 divisors (see below), whose sum is σ = 646379100. Its totient is φ = 645867040.

The previous prime is 646123057. The next prime is 646123087. The reversal of 646123069 is 960321646.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 604520569 + 41602500 = 24587^2 + 6450^2 .

It is a cyclic number.

It is not a de Polignac number, because 646123069 - 2¹⁹ = 645598781 is a prime.

It is a super-2 number, since 2×646123069² = 834950040587957522, 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 (646123019) 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, 124192 + ... + 129289.

It is an arithmetic number, because the mean of its divisors is an integer number (161594775).

Almost surely, 2^646123069 is an apocalyptic number.

It is an amenable number.

646123069 is a deficient number, since it is larger than the sum of its proper divisors (256031).

646123069 is a wasteful number, since it uses less digits than its factorization.

646123069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256030.

The product of its (nonzero) digits is 46656, while the sum is 37.

The square root of 646123069 is about 25418.9509815020. The cubic root of 646123069 is about 864.5134394832.

The spelling of 646123069 in words is "six hundred forty-six million, one hundred twenty-three thousand, sixty-nine".