820899517 has 2 divisors, whose sum is σ = 820899518. Its totient is φ = 820899516.

The previous prime is 820899511. The next prime is 820899523. The reversal of 820899517 is 715998028.

It is a balanced prime because it is at equal distance from previous prime (820899511) and next prime (820899523).

It can be written as a sum of positive squares in only one way, i.e., 545969956 + 274929561 = 23366^2 + 16581^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820899517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (820899511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410449758 + 410449759.

It is an arithmetic number, because the mean of its divisors is an integer number (410449759).

Almost surely, 2^820899517 is an apocalyptic number.

It is an amenable number.

820899517 is a deficient number, since it is larger than the sum of its proper divisors (1).

820899517 is an equidigital number, since it uses as much as digits as its factorization.

820899517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 362880, while the sum is 49.

The square root of 820899517 is about 28651.3440696942. The cubic root of 820899517 is about 936.3322888951.

The spelling of 820899517 in words is "eight hundred twenty million, eight hundred ninety-nine thousand, five hundred seventeen".