83972040021 has 6 divisors (see below), whose sum is σ = 121292946710. Its totient is φ = 55981360008.

The previous prime is 83972040013. The next prime is 83972040091. The reversal of 83972040021 is 12004027938.

It can be written as a sum of positive squares in only one way, i.e., 72636179121 + 11335860900 = 269511^2 + 106470^2 .

It is not a de Polignac number, because 83972040021 - 2³ = 83972040013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (83972040011) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4665113326 + ... + 4665113343.

Almost surely, 2^83972040021 is an apocalyptic number.

It is an amenable number.

83972040021 is a deficient number, since it is larger than the sum of its proper divisors (37320906689).

83972040021 is a wasteful number, since it uses less digits than its factorization.

83972040021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9330226675 (or 9330226672 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

Adding to 83972040021 its reverse (12004027938), we get a palindrome (95976067959).

The spelling of 83972040021 in words is "eighty-three billion, nine hundred seventy-two million, forty thousand, twenty-one".