81234779 has 2 divisors, whose sum is σ = 81234780. Its totient is φ = 81234778.

The previous prime is 81234767. The next prime is 81234793. The reversal of 81234779 is 97743218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81234779 - 2⁴ = 81234763 is a prime.

It is a super-3 number, since 3×81234779³ (a number of 25 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (81234749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40617389 + 40617390.

It is an arithmetic number, because the mean of its divisors is an integer number (40617390).

Almost surely, 2^81234779 is an apocalyptic number.

81234779 is a deficient number, since it is larger than the sum of its proper divisors (1).

81234779 is an equidigital number, since it uses as much as digits as its factorization.

81234779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 41.

The square root of 81234779 is about 9013.0338399453. The cubic root of 81234779 is about 433.0925047754.

The spelling of 81234779 in words is "eighty-one million, two hundred thirty-four thousand, seven hundred seventy-nine".