205551979956 has 36 divisors (see below), whose sum is σ = 519688190112. Its totient is φ = 68504342544.

The previous prime is 205551979951. The next prime is 205551979979. The reversal of 205551979956 is 659979155502.

205551979956 is a `hidden beast` number, since 2 + 0 + 5 + 551 + 9 + 79 + 9 + 5 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a junction number, because it is equal to n+sod(n) for n = 205551979893 and 205551979902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205551979951) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 347446 + ... + 729261.

Almost surely, 2^205551979956 is an apocalyptic number.

It is an amenable number.

205551979956 is an abundant number, since it is smaller than the sum of its proper divisors (314136210156).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

205551979956 is a wasteful number, since it uses less digits than its factorization.

205551979956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1082020 (or 1082015 counting only the distinct ones).

The product of its (nonzero) digits is 38272500, while the sum is 63.

The spelling of 205551979956 in words is "two hundred five billion, five hundred fifty-one million, nine hundred seventy-nine thousand, nine hundred fifty-six".