820628549 has 4 divisors (see below), whose sum is σ = 883753836. Its totient is φ = 757503264.

The previous prime is 820628533. The next prime is 820628561. The reversal of 820628549 is 945826028.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 446476900 + 374151649 = 21130^2 + 19343^2 .

It is a cyclic number.

It is not a de Polignac number, because 820628549 - 2⁴ = 820628533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820628849) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31562624 + ... + 31562649.

It is an arithmetic number, because the mean of its divisors is an integer number (220938459).

Almost surely, 2^820628549 is an apocalyptic number.

It is an amenable number.

820628549 is a deficient number, since it is larger than the sum of its proper divisors (63125287).

820628549 is a wasteful number, since it uses less digits than its factorization.

820628549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63125286.

The product of its (nonzero) digits is 276480, while the sum is 44.

The square root of 820628549 is about 28646.6149658210. The cubic root of 820628549 is about 936.2292539504.

The spelling of 820628549 in words is "eight hundred twenty million, six hundred twenty-eight thousand, five hundred forty-nine".