205136431 has 4 divisors (see below), whose sum is σ = 205893664. Its totient is φ = 204379200.

The previous prime is 205136429. The next prime is 205136443. The reversal of 205136431 is 134631502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 134631502 = 2 ⋅67315751.

It is a cyclic number.

It is not a de Polignac number, because 205136431 - 2¹ = 205136429 is a prime.

It is a super-2 number, since 2×205136431² = 84161910646835522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 205136396 and 205136405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205136411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 378210 + ... + 378751.

It is an arithmetic number, because the mean of its divisors is an integer number (51473416).

Almost surely, 2^205136431 is an apocalyptic number.

205136431 is a deficient number, since it is larger than the sum of its proper divisors (757233).

205136431 is an equidigital number, since it uses as much as digits as its factorization.

205136431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 757232.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 205136431 is about 14322.5846480305. The cubic root of 205136431 is about 589.7676294547.

Adding to 205136431 its reverse (134631502), we get a palindrome (339767933).

The spelling of 205136431 in words is "two hundred five million, one hundred thirty-six thousand, four hundred thirty-one".