646543653 has 32 divisors (see below), whose sum is σ = 1005312000. Its totient is φ = 361958976.

The previous prime is 646543649. The next prime is 646543687. The reversal of 646543653 is 356345646.

It is a happy number.

It is not a de Polignac number, because 646543653 - 2² = 646543649 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646543633) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 461448 + ... + 462846.

It is an arithmetic number, because the mean of its divisors is an integer number (31416000).

Almost surely, 2^646543653 is an apocalyptic number.

It is an amenable number.

646543653 is a deficient number, since it is larger than the sum of its proper divisors (358768347).

646543653 is a wasteful number, since it uses less digits than its factorization.

646543653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1841.

The product of its digits is 777600, while the sum is 42.

The square root of 646543653 is about 25427.2226757072. Note that the first 3 decimals coincide. The cubic root of 646543653 is about 864.7009794287.

The spelling of 646543653 in words is "six hundred forty-six million, five hundred forty-three thousand, six hundred fifty-three".