81153439 has 2 divisors, whose sum is σ = 81153440. Its totient is φ = 81153438.

The previous prime is 81153437. The next prime is 81153481. The reversal of 81153439 is 93435118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81153439 - 2¹ = 81153437 is a prime.

Together with 81153437, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81153431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40576719 + 40576720.

It is an arithmetic number, because the mean of its divisors is an integer number (40576720).

Almost surely, 2^81153439 is an apocalyptic number.

81153439 is a deficient number, since it is larger than the sum of its proper divisors (1).

81153439 is an equidigital number, since it uses as much as digits as its factorization.

81153439 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 34.

The square root of 81153439 is about 9008.5203557521. The cubic root of 81153439 is about 432.9479053435.

The spelling of 81153439 in words is "eighty-one million, one hundred fifty-three thousand, four hundred thirty-nine".