81894073 has 2 divisors, whose sum is σ = 81894074. Its totient is φ = 81894072.

The previous prime is 81894041. The next prime is 81894077. The reversal of 81894073 is 37049818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57805609 + 24088464 = 7603^2 + 4908^2 .

It is a cyclic number.

It is not a de Polignac number, because 81894073 - 2⁵ = 81894041 is a prime.

It is not a weakly prime, because it can be changed into another prime (81894077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40947036 + 40947037.

It is an arithmetic number, because the mean of its divisors is an integer number (40947037).

Almost surely, 2^81894073 is an apocalyptic number.

It is an amenable number.

81894073 is a deficient number, since it is larger than the sum of its proper divisors (1).

81894073 is an equidigital number, since it uses as much as digits as its factorization.

81894073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48384, while the sum is 40.

The square root of 81894073 is about 9049.5344079129. The cubic root of 81894073 is about 434.2609956530.

The spelling of 81894073 in words is "eighty-one million, eight hundred ninety-four thousand, seventy-three".