205775640625 has 63 divisors (see below), whose sum is σ = 272895198303. Its totient is φ = 155139750000.

The previous prime is 205775640619. The next prime is 205775640643. The reversal of 205775640625 is 526046577502.

The square root of 205775640625 is 453625.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 3 ways, for example, as 180279215649 + 25496424976 = 424593^2 + 159676^2 .

It is not a de Polignac number, because 205775640625 - 2²¹ = 205773543473 is a prime.

It is a super-2 number, since 2×205775640625² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 1077359280 + ... + 1077359470.

Almost surely, 2^205775640625 is an apocalyptic number.

205775640625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

205775640625 is the 453625-th square number.

205775640625 is the 226813-rd centered octagonal number.

It is an amenable number.

205775640625 is a deficient number, since it is larger than the sum of its proper divisors (67119557678).

205775640625 is an frugal number, since it uses more digits than its factorization.

205775640625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450 (or 215 counting only the distinct ones).

The product of its (nonzero) digits is 3528000, while the sum is 49.

Multiplying 205775640625 by its sum of digits (49), we get a square (10083006390625 = 3175375²).

It can be divided in two parts, 205775 and 640625, that added together give a square (846400 = 920²).

The spelling of 205775640625 in words is "two hundred five billion, seven hundred seventy-five million, six hundred forty thousand, six hundred twenty-five".