81625541 has 2 divisors, whose sum is σ = 81625542. Its totient is φ = 81625540.

The previous prime is 81625519. The next prime is 81625601. The reversal of 81625541 is 14552618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78836641 + 2788900 = 8879^2 + 1670^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81625541 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 81625498 and 81625507.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81621541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40812770 + 40812771.

It is an arithmetic number, because the mean of its divisors is an integer number (40812771).

Almost surely, 2^81625541 is an apocalyptic number.

It is an amenable number.

81625541 is a deficient number, since it is larger than the sum of its proper divisors (1).

81625541 is an equidigital number, since it uses as much as digits as its factorization.

81625541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9600, while the sum is 32.

The square root of 81625541 is about 9034.6854400139. The cubic root of 81625541 is about 433.7858262839.

The spelling of 81625541 in words is "eighty-one million, six hundred twenty-five thousand, five hundred forty-one".