1968404561 has 4 divisors (see below), whose sum is σ = 2053987392. Its totient is φ = 1882821732.

The previous prime is 1968404521. The next prime is 1968404563. The reversal of 1968404561 is 1654048691.

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 a de Polignac number, because none of the positive numbers 2^k-1968404561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1968404563) 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, 42791381 + ... + 42791426.

It is an arithmetic number, because the mean of its divisors is an integer number (513496848).

Almost surely, 2^1968404561 is an apocalyptic number.

It is an amenable number.

1968404561 is a deficient number, since it is larger than the sum of its proper divisors (85582831).

1968404561 is an equidigital number, since it uses as much as digits as its factorization.

1968404561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85582830.

The product of its (nonzero) digits is 207360, while the sum is 44.

The square root of 1968404561 is about 44366.7055459384. The cubic root of 1968404561 is about 1253.2511762312.

The spelling of 1968404561 in words is "one billion, nine hundred sixty-eight million, four hundred four thousand, five hundred sixty-one".