821787575625 has 315 divisors, whose sum is σ = 1656514957251. Its totient is φ = 407283552000.

The previous prime is 821787575563. The next prime is 821787575627. The reversal of 821787575625 is 526575787128.

The square root of 821787575625 is 906525.

It is a perfect power (a square), and thus also a powerful number.

821787575625 is a `hidden beast` number, since 8 + 2 + 17 + 8 + 7 + 57 + 562 + 5 = 666.

It can be written as a sum of positive squares in 7 ways, for example, as 401323517001 + 420464058624 = 633501^2 + 648432^2 .

It is not a de Polignac number, because 821787575625 - 2¹⁵ = 821787542857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821787575627) by changing a digit.

It is a polite number, since it can be written in 314 ways as a sum of consecutive naturals, for example, 10402374336 + ... + 10402374414.

Almost surely, 2^821787575625 is an apocalyptic number.

821787575625 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

821787575625 is the 906525-th square number.

821787575625 is the 453263-rd centered octagonal number.

It is an amenable number.

821787575625 is an abundant number, since it is smaller than the sum of its proper divisors (834727381626).

821787575625 is an frugal number, since it uses more digits than its factorization.

821787575625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230 (or 104 counting only the distinct ones).

The product of its digits is 65856000, while the sum is 63.

The spelling of 821787575625 in words is "eight hundred twenty-one billion, seven hundred eighty-seven million, five hundred seventy-five thousand, six hundred twenty-five".