205621057 has 8 divisors (see below), whose sum is σ = 212115392. Its totient is φ = 199227600.

The previous prime is 205621051. The next prime is 205621067. The reversal of 205621057 is 750126502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 205621057 - 2¹⁹ = 205096769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205621051) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21069 + ... + 29242.

It is an arithmetic number, because the mean of its divisors is an integer number (26514424).

Almost surely, 2^205621057 is an apocalyptic number.

It is an amenable number.

205621057 is a deficient number, since it is larger than the sum of its proper divisors (6494335).

205621057 is an equidigital number, since it uses as much as digits as its factorization.

205621057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50439.

The product of its (nonzero) digits is 4200, while the sum is 28.

The square root of 205621057 is about 14339.4929129311. The cubic root of 205621057 is about 590.2316977565.

Adding to 205621057 its reverse (750126502), we get a palindrome (955747559).

Subtracting 205621057 from its reverse (750126502), we obtain a palindrome (544505445).

The spelling of 205621057 in words is "two hundred five million, six hundred twenty-one thousand, fifty-seven".