205507981 has 8 divisors (see below), whose sum is σ = 235025280. Its totient is φ = 176030448.

The previous prime is 205507979. The next prime is 205507987. The reversal of 205507981 is 189705502.

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 205507981 - 2¹ = 205507979 is a prime.

It is a super-2 number, since 2×205507981² = 84467060509392722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 205507981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205507987) 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 7 ways as a sum of consecutive naturals, for example, 2115 + ... + 20383.

It is an arithmetic number, because the mean of its divisors is an integer number (29378160).

Almost surely, 2^205507981 is an apocalyptic number.

It is an amenable number.

205507981 is a deficient number, since it is larger than the sum of its proper divisors (29517299).

205507981 is a wasteful number, since it uses less digits than its factorization.

205507981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19883.

The product of its (nonzero) digits is 25200, while the sum is 37.

The square root of 205507981 is about 14335.5495534702. The cubic root of 205507981 is about 590.1234836817.

The spelling of 205507981 in words is "two hundred five million, five hundred seven thousand, nine hundred eighty-one".