3965121961 has 4 divisors (see below), whose sum is σ = 4137518592. Its totient is φ = 3792725332.

The previous prime is 3965121911. The next prime is 3965121967. The reversal of 3965121961 is 1691215693.

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 3965121961 - 2⁷ = 3965121833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3965121967) 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, 86198281 + ... + 86198326.

It is an arithmetic number, because the mean of its divisors is an integer number (1034379648).

Almost surely, 2^3965121961 is an apocalyptic number.

It is an amenable number.

3965121961 is a deficient number, since it is larger than the sum of its proper divisors (172396631).

3965121961 is a wasteful number, since it uses less digits than its factorization.

3965121961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172396630.

The product of its digits is 87480, while the sum is 43.

The square root of 3965121961 is about 62969.2143908434. The cubic root of 3965121961 is about 1582.7737903264.

The spelling of 3965121961 in words is "three billion, nine hundred sixty-five million, one hundred twenty-one thousand, nine hundred sixty-one".