3121263661561 has 8 divisors (see below), whose sum is σ = 3285618793920. Its totient is φ = 2956916338992.

The previous prime is 3121263661519. The next prime is 3121263661601. The reversal of 3121263661561 is 1651663621213.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3121263661561 - 2⁷ = 3121263661433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3121263661501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1123045 + ... + 2739298.

It is an arithmetic number, because the mean of its divisors is an integer number (410702349240).

Almost surely, 2^{3121263661561} is an apocalyptic number.

It is an amenable number.

3121263661561 is a deficient number, since it is larger than the sum of its proper divisors (164355132359).

3121263661561 is a wasteful number, since it uses less digits than its factorization.

3121263661561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3904895.

The product of its digits is 233280, while the sum is 43.

The spelling of 3121263661561 in words is "three trillion, one hundred twenty-one billion, two hundred sixty-three million, six hundred sixty-one thousand, five hundred sixty-one".