810261021025 has 27 divisors (see below), whose sum is σ = 1020323086419. Its totient is φ = 638296420080.

The previous prime is 810261021013. The next prime is 810261021107. The reversal of 810261021025 is 520120162018.

The square root of 810261021025 is 900145.

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

It can be written as a sum of positive squares in only one way, i.e., 291693967569 + 518567053456 = 540087^2 + 720116^2 .

It is not a de Polignac number, because 810261021025 - 2³¹ = 808113537377 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 810261020984 and 810261021002.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 301547232 + ... + 301549918.

Almost surely, 2^810261021025 is an apocalyptic number.

810261021025 is the 900145-th square number.

810261021025 is the 450073-rd centered octagonal number.

It is an amenable number.

810261021025 is a deficient number, since it is larger than the sum of its proper divisors (210062065394).

810261021025 is an frugal number, since it uses more digits than its factorization.

810261021025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5518 (or 2759 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 28.

The spelling of 810261021025 in words is "eight hundred ten billion, two hundred sixty-one million, twenty-one thousand, twenty-five".