6661948121765 has 32 divisors (see below), whose sum is σ = 8327964091392. Its totient is φ = 5110417728000.

The previous prime is 6661948121707. The next prime is 6661948121767. The reversal of 6661948121765 is 5671218491666.

It is a happy number.

It is not a de Polignac number, because 6661948121765 - 2¹⁰ = 6661948120741 is a prime.

It is a super-2 number, since 2×6661948121765² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 6661948121698 and 6661948121707.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6661948121767) 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 31 ways as a sum of consecutive naturals, for example, 13007945 + ... + 13510385.

It is an arithmetic number, because the mean of its divisors is an integer number (260248877856).

Almost surely, 2^{6661948121765} is an apocalyptic number.

It is an amenable number.

6661948121765 is a deficient number, since it is larger than the sum of its proper divisors (1666015969627).

6661948121765 is a wasteful number, since it uses less digits than its factorization.

6661948121765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503261.

The product of its digits is 26127360, while the sum is 62.

The spelling of 6661948121765 in words is "six trillion, six hundred sixty-one billion, nine hundred forty-eight million, one hundred twenty-one thousand, seven hundred sixty-five".