81884581929637 has 2 divisors, whose sum is σ = 81884581929638. Its totient is φ = 81884581929636.

The previous prime is 81884581929611. The next prime is 81884581929641. The reversal of 81884581929637 is 73692918548818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49431951777796 + 32452630151841 = 7030786^2 + 5696721^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81884581929637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81884581929737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40942290964818 + 40942290964819.

It is an arithmetic number, because the mean of its divisors is an integer number (40942290964819).

Almost surely, 2^{81884581929637} is an apocalyptic number.

It is an amenable number.

81884581929637 is a deficient number, since it is larger than the sum of its proper divisors (1).

81884581929637 is an equidigital number, since it uses as much as digits as its factorization.

81884581929637 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1672151040, while the sum is 79.

It can be divided in two parts, 818845819 and 29637, that added together give a square (818875456 = 28616²).

The spelling of 81884581929637 in words is "eighty-one trillion, eight hundred eighty-four billion, five hundred eighty-one million, nine hundred twenty-nine thousand, six hundred thirty-seven".