243902563561 has 4 divisors (see below), whose sum is σ = 251770388224. Its totient is φ = 236034738900.

The previous prime is 243902563559. The next prime is 243902563573. The reversal of 243902563561 is 165365209342.

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 243902563561 - 2¹ = 243902563559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243902543561) 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, 3933912285 + ... + 3933912346.

It is an arithmetic number, because the mean of its divisors is an integer number (62942597056).

Almost surely, 2^243902563561 is an apocalyptic number.

It is an amenable number.

243902563561 is a deficient number, since it is larger than the sum of its proper divisors (7867824663).

243902563561 is an equidigital number, since it uses as much as digits as its factorization.

243902563561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7867824662.

The product of its (nonzero) digits is 1166400, while the sum is 46.

The spelling of 243902563561 in words is "two hundred forty-three billion, nine hundred two million, five hundred sixty-three thousand, five hundred sixty-one".