10661121765 has 96 divisors (see below), whose sum is σ = 21496700160. Its totient is φ = 4787278848.

The previous prime is 10661121763. The next prime is 10661121847. The reversal of 10661121765 is 56712116601.

It is a happy number.

10661121765 is a `hidden beast` number, since 10 + 6 + 611 + 21 + 7 + 6 + 5 = 666.

It is not a de Polignac number, because 10661121765 - 2¹ = 10661121763 is a prime.

It is a super-2 number, since 2×10661121765² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10661121763) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 4568539 + ... + 4570871.

It is an arithmetic number, because the mean of its divisors is an integer number (223923960).

Almost surely, 2^10661121765 is an apocalyptic number.

10661121765 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

10661121765 is an abundant number, since it is smaller than the sum of its proper divisors (10835578395).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

10661121765 is a wasteful number, since it uses less digits than its factorization.

10661121765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2603 (or 2600 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 36.

The spelling of 10661121765 in words is "ten billion, six hundred sixty-one million, one hundred twenty-one thousand, seven hundred sixty-five".