820159409 has 2 divisors, whose sum is σ = 820159410. Its totient is φ = 820159408.

The previous prime is 820159397. The next prime is 820159421. The reversal of 820159409 is 904951028.

It is a balanced prime because it is at equal distance from previous prime (820159397) and next prime (820159421).

It can be written as a sum of positive squares in only one way, i.e., 631014400 + 189145009 = 25120^2 + 13753^2 .

It is a cyclic number.

It is not a de Polignac number, because 820159409 - 2⁴ = 820159393 is a prime.

It is a super-2 number, since 2×820159409² = 1345322912342458562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (820159499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410079704 + 410079705.

It is an arithmetic number, because the mean of its divisors is an integer number (410079705).

Almost surely, 2^820159409 is an apocalyptic number.

It is an amenable number.

820159409 is a deficient number, since it is larger than the sum of its proper divisors (1).

820159409 is an equidigital number, since it uses as much as digits as its factorization.

820159409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 820159409 is about 28638.4253931671. The cubic root of 820159409 is about 936.0508109272.

The spelling of 820159409 in words is "eight hundred twenty million, one hundred fifty-nine thousand, four hundred nine".