81103573 has 2 divisors, whose sum is σ = 81103574. Its totient is φ = 81103572.

The previous prime is 81103523. The next prime is 81103577. The reversal of 81103573 is 37530118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75377124 + 5726449 = 8682^2 + 2393^2 .

It is a cyclic number.

It is not a de Polignac number, because 81103573 - 2²⁵ = 47549141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81103577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40551786 + 40551787.

It is an arithmetic number, because the mean of its divisors is an integer number (40551787).

Almost surely, 2^81103573 is an apocalyptic number.

It is an amenable number.

81103573 is a deficient number, since it is larger than the sum of its proper divisors (1).

81103573 is an equidigital number, since it uses as much as digits as its factorization.

81103573 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 81103573 is about 9005.7522173331. The cubic root of 81103573 is about 432.8592099701.

The spelling of 81103573 in words is "eighty-one million, one hundred three thousand, five hundred seventy-three".