81155423 has 2 divisors, whose sum is σ = 81155424. Its totient is φ = 81155422.

The previous prime is 81155411. The next prime is 81155443. The reversal of 81155423 is 32455118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81155423 - 2⁴ = 81155407 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81155443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40577711 + 40577712.

It is an arithmetic number, because the mean of its divisors is an integer number (40577712).

Almost surely, 2^81155423 is an apocalyptic number.

81155423 is a deficient number, since it is larger than the sum of its proper divisors (1).

81155423 is an equidigital number, since it uses as much as digits as its factorization.

81155423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4800, while the sum is 29.

The square root of 81155423 is about 9008.6304730519. The cubic root of 81155423 is about 432.9514334817.

The spelling of 81155423 in words is "eighty-one million, one hundred fifty-five thousand, four hundred twenty-three".