199556981 has 8 divisors (see below), whose sum is σ = 226218720. Its totient is φ = 174511152.

The previous prime is 199556969. The next prime is 199557011. The reversal of 199556981 is 189655991.

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 199556981 - 2¹⁰ = 199555957 is a prime.

It is a super-2 number, since 2×199556981² = 79645977331668722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199556941) 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, 403715 + ... + 404208.

It is an arithmetic number, because the mean of its divisors is an integer number (28277340).

Almost surely, 2^199556981 is an apocalyptic number.

It is an amenable number.

199556981 is a deficient number, since it is larger than the sum of its proper divisors (26661739).

199556981 is a wasteful number, since it uses less digits than its factorization.

199556981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 807955.

The product of its digits is 874800, while the sum is 53.

The square root of 199556981 is about 14126.4638533499. The cubic root of 199556981 is about 584.3714299533.

The spelling of 199556981 in words is "one hundred ninety-nine million, five hundred fifty-six thousand, nine hundred eighty-one".