1983972121765 has 12 divisors (see below), whose sum is σ = 2465692825284. Its totient is φ = 1532447428736.

The previous prime is 1983972121717. The next prime is 1983972121811. The reversal of 1983972121765 is 5671212793891.

It can be written as a sum of positive squares in 6 ways, for example, as 150577441 + 1983821544324 = 12271^2 + 1408482^2 .

It is not a de Polignac number, because 1983972121765 - 2¹⁵ = 1983972088997 is a prime.

It is a super-2 number, since 2×1983972121765² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 235902112 + ... + 235910521.

It is an arithmetic number, because the mean of its divisors is an integer number (205474402107).

Almost surely, 2^{1983972121765} is an apocalyptic number.

It is an amenable number.

1983972121765 is a deficient number, since it is larger than the sum of its proper divisors (481720703519).

1983972121765 is an equidigital number, since it uses as much as digits as its factorization.

1983972121765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471812696 (or 471812667 counting only the distinct ones).

The product of its digits is 11430720, while the sum is 61.

The spelling of 1983972121765 in words is "one trillion, nine hundred eighty-three billion, nine hundred seventy-two million, one hundred twenty-one thousand, seven hundred sixty-five".