819520643957 has 2 divisors, whose sum is σ = 819520643958. Its totient is φ = 819520643956.

The previous prime is 819520643933. The next prime is 819520644029. The reversal of 819520643957 is 759346025918.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 632766157156 + 186754486801 = 795466^2 + 432151^2 .

It is a cyclic number.

It is not a de Polignac number, because 819520643957 - 2²⁰ = 819519595381 is a prime.

It is a super-2 number, since 2×819520643957² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 819520643896 and 819520643905.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (819520640957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 409760321978 + 409760321979.

It is an arithmetic number, because the mean of its divisors is an integer number (409760321979).

It is a 1-persistent number, because it is pandigital, but 2⋅819520643957 = 1639041287914 is not.

Almost surely, 2^819520643957 is an apocalyptic number.

It is an amenable number.

819520643957 is a deficient number, since it is larger than the sum of its proper divisors (1).

819520643957 is an equidigital number, since it uses as much as digits as its factorization.

819520643957 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16329600, while the sum is 59.

The spelling of 819520643957 in words is "eight hundred nineteen billion, five hundred twenty million, six hundred forty-three thousand, nine hundred fifty-seven".