820660755 has 16 divisors (see below), whose sum is σ = 1334584224. Its totient is φ = 430510080.

The previous prime is 820660751. The next prime is 820660759. The reversal of 820660755 is 557066028.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (820660751) and next prime (820660759).

It is not a de Polignac number, because 820660755 - 2² = 820660751 is a prime.

It is not an unprimeable number, because it can be changed into a prime (820660751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 447534 + ... + 449363.

It is an arithmetic number, because the mean of its divisors is an integer number (83411514).

Almost surely, 2^820660755 is an apocalyptic number.

820660755 is a deficient number, since it is larger than the sum of its proper divisors (513923469).

820660755 is a wasteful number, since it uses less digits than its factorization.

820660755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 896966.

The product of its (nonzero) digits is 100800, while the sum is 39.

The square root of 820660755 is about 28647.1770860586. The cubic root of 820660755 is about 936.2415013937.

The spelling of 820660755 in words is "eight hundred twenty million, six hundred sixty thousand, seven hundred fifty-five".