205790156881 has 3 divisors (see below), whose sum is σ = 205790610523. Its totient is φ = 205789703240.

The previous prime is 205790156849. The next prime is 205790156909. The reversal of 205790156881 is 188651097502.

The square root of 205790156881 is 453641.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 77511571281 + 128278585600 = 278409^2 + 358160^2 .

It is not a de Polignac number, because 205790156881 - 2⁵ = 205790156849 is a prime.

It is a super-2 number, since 2×205790156881² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205790156801) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 226821 + ... + 680461.

Almost surely, 2^205790156881 is an apocalyptic number.

205790156881 is the 453641-st square number.

205790156881 is the 226821-st centered octagonal number.

It is an amenable number.

205790156881 is a deficient number, since it is larger than the sum of its proper divisors (453642).

205790156881 is an frugal number, since it uses more digits than its factorization.

205790156881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 907282 (or 453641 counting only the distinct ones).

The product of its (nonzero) digits is 1209600, while the sum is 52.

The spelling of 205790156881 in words is "two hundred five billion, seven hundred ninety million, one hundred fifty-six thousand, eight hundred eighty-one".