199998521 has 8 divisors (see below), whose sum is σ = 203985864. Its totient is φ = 196019200.

The previous prime is 199998517. The next prime is 199998559. The reversal of 199998521 is 125899991.

It can be written as a sum of positive squares in 4 ways, for example, as 83466496 + 116532025 = 9136^2 + 10795^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 199998521 - 2² = 199998517 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (199998581) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 83675 + ... + 86031.

It is an arithmetic number, because the mean of its divisors is an integer number (25498233).

Almost surely, 2^199998521 is an apocalyptic number.

It is an amenable number.

199998521 is a deficient number, since it is larger than the sum of its proper divisors (3987343).

199998521 is a wasteful number, since it uses less digits than its factorization.

199998521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4011.

The product of its digits is 524880, while the sum is 53.

The square root of 199998521 is about 14142.0833330878. The cubic root of 199998521 is about 584.8021060983.

The spelling of 199998521 in words is "one hundred ninety-nine million, nine hundred ninety-eight thousand, five hundred twenty-one".