999820025 has 12 divisors (see below), whose sum is σ = 1243466172. Its totient is φ = 797475840.

The previous prime is 999819943. The next prime is 999820069. The reversal of 999820025 is 520028999.

It can be written as a sum of positive squares in 6 ways, for example, as 1449616 + 998370409 = 1204^2 + 31597^2 .

It is not a de Polignac number, because 999820025 - 2¹⁰ = 999819001 is a prime.

It is a hoax number, since the sum of its digits (44) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 50912 + ... + 67761.

It is an arithmetic number, because the mean of its divisors is an integer number (103622181).

Almost surely, 2^999820025 is an apocalyptic number.

It is an amenable number.

999820025 is a deficient number, since it is larger than the sum of its proper divisors (243646147).

999820025 is a wasteful number, since it uses less digits than its factorization.

999820025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119020 (or 119015 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 44.

The square root of 999820025 is about 31619.9308190262. The cubic root of 999820025 is about 999.9400047340.

The spelling of 999820025 in words is "nine hundred ninety-nine million, eight hundred twenty thousand, twenty-five".