646354521 has 12 divisors (see below), whose sum is σ = 982761520. Its totient is φ = 408223800.

The previous prime is 646354519. The next prime is 646354547. The reversal of 646354521 is 125453646.

646354521 is a `hidden beast` number, since 646 + 3 + 5 + 4 + 5 + 2 + 1 = 666.

It is not a de Polignac number, because 646354521 - 2¹ = 646354519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646354421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1889755 + ... + 1890096.

Almost surely, 2^646354521 is an apocalyptic number.

It is an amenable number.

646354521 is a deficient number, since it is larger than the sum of its proper divisors (336406999).

646354521 is a wasteful number, since it uses less digits than its factorization.

646354521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3779876 (or 3779873 counting only the distinct ones).

The product of its digits is 86400, while the sum is 36.

The square root of 646354521 is about 25423.5033187797. The cubic root of 646354521 is about 864.6166548440.

The spelling of 646354521 in words is "six hundred forty-six million, three hundred fifty-four thousand, five hundred twenty-one".