205106721534 has 128 divisors (see below), whose sum is σ = 535908764160. Its totient is φ = 57326227200.

The previous prime is 205106721529. The next prime is 205106721563. The reversal of 205106721534 is 435127601502.

205106721534 is a `hidden beast` number, since 2 + 0 + 51 + 0 + 6 + 72 + 1 + 534 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 10190709 + ... + 10210815.

It is an arithmetic number, because the mean of its divisors is an integer number (4186787220).

Almost surely, 2^205106721534 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205106721534, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (267954382080).

205106721534 is an abundant number, since it is smaller than the sum of its proper divisors (330802042626).

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

205106721534 is a wasteful number, since it uses less digits than its factorization.

205106721534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21463 (or 21457 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The spelling of 205106721534 in words is "two hundred five billion, one hundred six million, seven hundred twenty-one thousand, five hundred thirty-four".