1998509725 has 12 divisors (see below), whose sum is σ = 2502691380. Its totient is φ = 1582976000.

The previous prime is 1998509717. The next prime is 1998509731. The reversal of 1998509725 is 5279058991.

It can be written as a sum of positive squares in 6 ways, for example, as 183494116 + 1815015609 = 13546^2 + 42603^2 .

It is not a de Polignac number, because 1998509725 - 2³ = 1998509717 is a prime.

It is a super-2 number, since 2×1998509725² = 7988082241839151250, which contains 22 as substring.

It is a congruent 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, 393220 + ... + 398269.

It is an arithmetic number, because the mean of its divisors is an integer number (208557615).

Almost surely, 2^1998509725 is an apocalyptic number.

It is an amenable number.

1998509725 is a deficient number, since it is larger than the sum of its proper divisors (504181655).

1998509725 is a wasteful number, since it uses less digits than its factorization.

1998509725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 791600 (or 791595 counting only the distinct ones).

The product of its (nonzero) digits is 2041200, while the sum is 55.

The square root of 1998509725 is about 44704.6946639836. The cubic root of 1998509725 is about 1259.6080339949.

The spelling of 1998509725 in words is "one billion, nine hundred ninety-eight million, five hundred nine thousand, seven hundred twenty-five".