81154589 has 2 divisors, whose sum is σ = 81154590. Its totient is φ = 81154588.

The previous prime is 81154573. The next prime is 81154637. The reversal of 81154589 is 98545118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70644025 + 10510564 = 8405^2 + 3242^2 .

It is a cyclic number.

It is not a de Polignac number, because 81154589 - 2⁴ = 81154573 is a prime.

It is a super-4 number, since 4×81154589⁴ (a number of 33 digits) contains 4444 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81154519) 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, 40577294 + 40577295.

It is an arithmetic number, because the mean of its divisors is an integer number (40577295).

Almost surely, 2^81154589 is an apocalyptic number.

It is an amenable number.

81154589 is a deficient number, since it is larger than the sum of its proper divisors (1).

81154589 is an equidigital number, since it uses as much as digits as its factorization.

81154589 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 57600, while the sum is 41.

The square root of 81154589 is about 9008.5841839881. The cubic root of 81154589 is about 432.9499503903.

The spelling of 81154589 in words is "eighty-one million, one hundred fifty-four thousand, five hundred eighty-nine".