1998406625 has 32 divisors (see below), whose sum is σ = 2572970400. Its totient is φ = 1548672000.

The previous prime is 1998406621. The next prime is 1998406651. The reversal of 1998406625 is 5266048991.

It can be written as a sum of positive squares in 16 ways, for example, as 1713877201 + 284529424 = 41399^2 + 16868^2 .

It is not a de Polignac number, because 1998406625 - 2² = 1998406621 is a prime.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1998406621) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 762317 + ... + 764933.

It is an arithmetic number, because the mean of its divisors is an integer number (80405325).

Almost surely, 2^1998406625 is an apocalyptic number.

It is an amenable number.

1998406625 is a deficient number, since it is larger than the sum of its proper divisors (574563775).

1998406625 is a wasteful number, since it uses less digits than its factorization.

1998406625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2822 (or 2812 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 50.

The square root of 1998406625 is about 44703.5415263713. The cubic root of 1998406625 is about 1259.5863732177.

The spelling of 1998406625 in words is "one billion, nine hundred ninety-eight million, four hundred six thousand, six hundred twenty-five".