205155100501 has 4 divisors (see below), whose sum is σ = 220936262092. Its totient is φ = 189373938912.

The previous prime is 205155100489. The next prime is 205155100543. The reversal of 205155100501 is 105001551502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 105001551502 = 2 ⋅52500775751.

It can be written as a sum of positive squares in 2 ways, for example, as 20001313476 + 185153787025 = 141426^2 + 430295^2 .

It is a cyclic number.

It is not a de Polignac number, because 205155100501 - 2²³ = 205146711893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205155100571) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7890580776 + ... + 7890580801.

It is an arithmetic number, because the mean of its divisors is an integer number (55234065523).

Almost surely, 2^205155100501 is an apocalyptic number.

It is an amenable number.

205155100501 is a deficient number, since it is larger than the sum of its proper divisors (15781161591).

205155100501 is a wasteful number, since it uses less digits than its factorization.

205155100501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15781161590.

The product of its (nonzero) digits is 1250, while the sum is 25.

The spelling of 205155100501 in words is "two hundred five billion, one hundred fifty-five million, one hundred thousand, five hundred one".