203563161661 has 4 divisors (see below), whose sum is σ = 207013384800. Its totient is φ = 200112938524.

The previous prime is 203563161649. The next prime is 203563161677. The reversal of 203563161661 is 166161365302.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 203563161661 - 2⁵ = 203563161629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (203563161611) 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, 1725111481 + ... + 1725111598.

It is an arithmetic number, because the mean of its divisors is an integer number (51753346200).

Almost surely, 2^203563161661 is an apocalyptic number.

It is an amenable number.

203563161661 is a deficient number, since it is larger than the sum of its proper divisors (3450223139).

203563161661 is an equidigital number, since it uses as much as digits as its factorization.

203563161661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3450223138.

The product of its (nonzero) digits is 116640, while the sum is 40.

The spelling of 203563161661 in words is "two hundred three billion, five hundred sixty-three million, one hundred sixty-one thousand, six hundred sixty-one".