91842781 has 2 divisors, whose sum is σ = 91842782. Its totient is φ = 91842780.

The previous prime is 91842767. The next prime is 91842809. The reversal of 91842781 is 18724819.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76562500 + 15280281 = 8750^2 + 3909^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91842781 is a prime.

It is a super-2 number, since 2×91842781² = 16870192843627922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91842761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45921390 + 45921391.

It is an arithmetic number, because the mean of its divisors is an integer number (45921391).

Almost surely, 2^91842781 is an apocalyptic number.

It is an amenable number.

91842781 is a deficient number, since it is larger than the sum of its proper divisors (1).

91842781 is an equidigital number, since it uses as much as digits as its factorization.

91842781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32256, while the sum is 40.

The square root of 91842781 is about 9583.4639353420. The cubic root of 91842781 is about 451.1784437505.

The spelling of 91842781 in words is "ninety-one million, eight hundred forty-two thousand, seven hundred eighty-one".