646405101 has 6 divisors (see below), whose sum is σ = 933696270. Its totient is φ = 430936728.

The previous prime is 646405091. The next prime is 646405129. The reversal of 646405101 is 101504646.

646405101 is a `hidden beast` number, since 6 + 4 + 640 + 5 + 10 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 409091076 + 237314025 = 20226^2 + 15405^2 .

It is not a de Polignac number, because 646405101 - 2⁶ = 646405037 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646405141) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35911386 + ... + 35911403.

It is an arithmetic number, because the mean of its divisors is an integer number (155616045).

Almost surely, 2^646405101 is an apocalyptic number.

It is an amenable number.

646405101 is a deficient number, since it is larger than the sum of its proper divisors (287291169).

646405101 is a wasteful number, since it uses less digits than its factorization.

646405101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71822795 (or 71822792 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 646405101 is about 25424.4980481425. The cubic root of 646405101 is about 864.6392075703.

Adding to 646405101 its reverse (101504646), we get a palindrome (747909747).

The spelling of 646405101 in words is "six hundred forty-six million, four hundred five thousand, one hundred one".