81883261 has 2 divisors, whose sum is σ = 81883262. Its totient is φ = 81883260.

The previous prime is 81883201. The next prime is 81883267. The reversal of 81883261 is 16238818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72080100 + 9803161 = 8490^2 + 3131^2 .

It is a cyclic number.

It is not a de Polignac number, because 81883261 - 2¹¹ = 81881213 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81883261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81883267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40941630 + 40941631.

It is an arithmetic number, because the mean of its divisors is an integer number (40941631).

Almost surely, 2^81883261 is an apocalyptic number.

It is an amenable number.

81883261 is a deficient number, since it is larger than the sum of its proper divisors (1).

81883261 is an equidigital number, since it uses as much as digits as its factorization.

81883261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18432, while the sum is 37.

The square root of 81883261 is about 9048.9370093951. The cubic root of 81883261 is about 434.2418838241.

It can be divided in two parts, 8188 and 3261, that added together give a square (11449 = 107²).

The spelling of 81883261 in words is "eighty-one million, eight hundred eighty-three thousand, two hundred sixty-one".