820541668 has 6 divisors (see below), whose sum is σ = 1435947926. Its totient is φ = 410270832.

The previous prime is 820541647. The next prime is 820541671. The reversal of 820541668 is 866145028.

It can be written as a sum of positive squares in only one way, i.e., 619412544 + 201129124 = 24888^2 + 14182^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 820541668.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102567705 + ... + 102567712.

Almost surely, 2^820541668 is an apocalyptic number.

It is an amenable number.

820541668 is a deficient number, since it is larger than the sum of its proper divisors (615406258).

820541668 is a wasteful number, since it uses less digits than its factorization.

820541668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205135421 (or 205135419 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 40.

The square root of 820541668 is about 28645.0984986961. The cubic root of 820541668 is about 936.1962128526.

The spelling of 820541668 in words is "eight hundred twenty million, five hundred forty-one thousand, six hundred sixty-eight".