81825949 has 4 divisors (see below), whose sum is σ = 83167420. Its totient is φ = 80484480.

The previous prime is 81825941. The next prime is 81825971. The reversal of 81825949 is 94952818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2295225 + 79530724 = 1515^2 + 8918^2 .

It is a cyclic number.

It is not a de Polignac number, because 81825949 - 2³ = 81825941 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81825899 and 81825908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81825941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 670644 + ... + 670765.

It is an arithmetic number, because the mean of its divisors is an integer number (20791855).

Almost surely, 2^81825949 is an apocalyptic number.

It is an amenable number.

81825949 is a deficient number, since it is larger than the sum of its proper divisors (1341471).

81825949 is a wasteful number, since it uses less digits than its factorization.

81825949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1341470.

The product of its digits is 207360, while the sum is 46.

The square root of 81825949 is about 9045.7696742732. The cubic root of 81825949 is about 434.1405481779.

The spelling of 81825949 in words is "eighty-one million, eight hundred twenty-five thousand, nine hundred forty-nine".