83894437657981 has 2 divisors, whose sum is σ = 83894437657982. Its totient is φ = 83894437657980.

The previous prime is 83894437657937. The next prime is 83894437657999. The reversal of 83894437657981 is 18975673449838.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83825194472100 + 69243185881 = 9155610^2 + 263141^2 .

It is a cyclic number.

It is not a de Polignac number, because 83894437657981 - 2³¹ = 83892290174333 is a prime.

It is a super-2 number, since 2×83894437657981² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 83894437657895 and 83894437657904.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (83894437657781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41947218828990 + 41947218828991.

It is an arithmetic number, because the mean of its divisors is an integer number (41947218828991).

Almost surely, 2^{83894437657981} is an apocalyptic number.

It is an amenable number.

83894437657981 is a deficient number, since it is larger than the sum of its proper divisors (1).

83894437657981 is an equidigital number, since it uses as much as digits as its factorization.

83894437657981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8778792960, while the sum is 82.

The spelling of 83894437657981 in words is "eighty-three trillion, eight hundred ninety-four billion, four hundred thirty-seven million, six hundred fifty-seven thousand, nine hundred eighty-one".