205421265 has 112 divisors (see below), whose sum is σ = 431883648. Its totient is φ = 91819008.

The previous prime is 205421233. The next prime is 205421267. The reversal of 205421265 is 562124502.

It is not a de Polignac number, because 205421265 - 2⁵ = 205421233 is a prime.

It is a super-2 number, since 2×205421265² = 84395792228400450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (205421267) by changing a digit.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 2117697 + ... + 2117793.

It is an arithmetic number, because the mean of its divisors is an integer number (3856104).

Almost surely, 2^205421265 is an apocalyptic number.

It is an amenable number.

205421265 is an abundant number, since it is smaller than the sum of its proper divisors (226462383).

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

205421265 is an frugal number, since it uses more digits than its factorization.

205421265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210 (or 195 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 205421265 is about 14332.5247252534. The cubic root of 205421265 is about 590.0404693106.

Adding to 205421265 its reverse (562124502), we get a palindrome (767545767).

The spelling of 205421265 in words is "two hundred five million, four hundred twenty-one thousand, two hundred sixty-five".