820105547125225 has 9 divisors (see below), whose sum is σ = 1016931055987717. Its totient is φ = 656084323150240.

The previous prime is 820105547125223. The next prime is 820105547125321. The reversal of 820105547125225 is 522521745501028.

The square root of 820105547125225 is 28637485.

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

It can be written as a sum of positive squares in 4 ways, for example, as 350379509354329 + 469726037770896 = 18718427^2 + 21673164^2 .

It is not a de Polignac number, because 820105547125225 - 2¹ = 820105547125223 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820105547125223) 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, 140323677 + ... + 146051173.

Almost surely, 2^{820105547125225} is an apocalyptic number.

820105547125225 is the 28637485-th square number.

820105547125225 is the 14318743-rd centered octagonal number.

It is an amenable number.

820105547125225 is a deficient number, since it is larger than the sum of its proper divisors (196825508862492).

820105547125225 is an frugal number, since it uses more digits than its factorization.

820105547125225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11455004 (or 5727502 counting only the distinct ones).

The product of its (nonzero) digits is 2240000, while the sum is 49.

The spelling of 820105547125225 in words is "eight hundred twenty trillion, one hundred five billion, five hundred forty-seven million, one hundred twenty-five thousand, two hundred twenty-five".