81894499 has 2 divisors, whose sum is σ = 81894500. Its totient is φ = 81894498.

The previous prime is 81894493. The next prime is 81894511. The reversal of 81894499 is 99449818.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81894499 - 2¹⁷ = 81763427 is a prime.

It is a super-2 number, since 2×81894499² = 13413417932922002, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81894493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40947249 + 40947250.

It is an arithmetic number, because the mean of its divisors is an integer number (40947250).

Almost surely, 2^81894499 is an apocalyptic number.

81894499 is a deficient number, since it is larger than the sum of its proper divisors (1).

81894499 is an equidigital number, since it uses as much as digits as its factorization.

81894499 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 746496, while the sum is 52.

The square root of 81894499 is about 9049.5579450048. The cubic root of 81894499 is about 434.2617486373.

The spelling of 81894499 in words is "eighty-one million, eight hundred ninety-four thousand, four hundred ninety-nine".