820657287522 has 18 divisors (see below), whose sum is σ = 1778099117067. Its totient is φ = 273551148036.

The previous prime is 820657287491. The next prime is 820657287529. The reversal of 820657287522 is 225782756028.

It can be written as a sum of positive squares in only one way, i.e., 410328643761 + 410328643761 = 640569^2 + 640569^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=640569.

It is not an unprimeable number, because it can be changed into a prime (820657287529) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3736653 + ... + 3950175.

Almost surely, 2^820657287522 is an apocalyptic number.

820657287522 is an abundant number, since it is smaller than the sum of its proper divisors (957441829545).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

820657287522 is an frugal number, since it uses more digits than its factorization.

820657287522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427054 (or 213528 counting only the distinct ones).

The product of its (nonzero) digits is 7526400, while the sum is 54.

The spelling of 820657287522 in words is "eight hundred twenty billion, six hundred fifty-seven million, two hundred eighty-seven thousand, five hundred twenty-two".