81094421 has 2 divisors, whose sum is σ = 81094422. Its totient is φ = 81094420.

The previous prime is 81094393. The next prime is 81094423. The reversal of 81094421 is 12449018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77193796 + 3900625 = 8786^2 + 1975^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81094421 is a prime.

Together with 81094423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81094423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40547210 + 40547211.

It is an arithmetic number, because the mean of its divisors is an integer number (40547211).

Almost surely, 2^81094421 is an apocalyptic number.

It is an amenable number.

81094421 is a deficient number, since it is larger than the sum of its proper divisors (1).

81094421 is an equidigital number, since it uses as much as digits as its factorization.

81094421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 81094421 is about 9005.2440833106. The cubic root of 81094421 is about 432.8429275945.

The spelling of 81094421 in words is "eighty-one million, ninety-four thousand, four hundred twenty-one".