820356389 has 4 divisors (see below), whose sum is σ = 820513356. Its totient is φ = 820199424.

The previous prime is 820356371. The next prime is 820356401. The reversal of 820356389 is 983653028.

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 337016164 + 483340225 = 18358^2 + 21985^2 .

It is a cyclic number.

It is not a de Polignac number, because 820356389 - 2⁸ = 820356133 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820356289) 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, 70364 + ... + 81189.

It is an arithmetic number, because the mean of its divisors is an integer number (205128339).

Almost surely, 2^820356389 is an apocalyptic number.

It is an amenable number.

820356389 is a deficient number, since it is larger than the sum of its proper divisors (156967).

820356389 is a wasteful number, since it uses less digits than its factorization.

820356389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156966.

The product of its (nonzero) digits is 311040, while the sum is 44.

The square root of 820356389 is about 28641.8642724247. The cubic root of 820356389 is about 936.1257429170.

The spelling of 820356389 in words is "eight hundred twenty million, three hundred fifty-six thousand, three hundred eighty-nine".