205440526421 has 4 divisors (see below), whose sum is σ = 221243643852. Its totient is φ = 189637408992.

The previous prime is 205440526409. The next prime is 205440526429. The reversal of 205440526421 is 124625044502.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13903003921 + 191537522500 = 117911^2 + 437650^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205440526421 is a prime.

It is a super-2 number, since 2×205440526421² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205440526429) 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, 7901558696 + ... + 7901558721.

It is an arithmetic number, because the mean of its divisors is an integer number (55310910963).

Almost surely, 2^205440526421 is an apocalyptic number.

It is an amenable number.

205440526421 is a deficient number, since it is larger than the sum of its proper divisors (15803117431).

205440526421 is a wasteful number, since it uses less digits than its factorization.

205440526421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15803117430.

The product of its (nonzero) digits is 76800, while the sum is 35.

The spelling of 205440526421 in words is "two hundred five billion, four hundred forty million, five hundred twenty-six thousand, four hundred twenty-one".