1968625561 has 4 divisors (see below), whose sum is σ = 2249857792. Its totient is φ = 1687393332.

The previous prime is 1968625543. The next prime is 1968625577. The reversal of 1968625561 is 1655268691.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1655268691 = 17497 ⋅94603.

It is a cyclic number.

It is not a de Polignac number, because 1968625561 - 2⁷ = 1968625433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1968625501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 140616105 + ... + 140616118.

It is an arithmetic number, because the mean of its divisors is an integer number (562464448).

Almost surely, 2^1968625561 is an apocalyptic number.

It is an amenable number.

1968625561 is a deficient number, since it is larger than the sum of its proper divisors (281232231).

1968625561 is an equidigital number, since it uses as much as digits as its factorization.

1968625561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281232230.

The product of its digits is 777600, while the sum is 49.

The square root of 1968625561 is about 44369.1960824174. The cubic root of 1968625561 is about 1253.2980768448.

The spelling of 1968625561 in words is "one billion, nine hundred sixty-eight million, six hundred twenty-five thousand, five hundred sixty-one".