81893047 has 2 divisors, whose sum is σ = 81893048. Its totient is φ = 81893046.

The previous prime is 81893023. The next prime is 81893057. The reversal of 81893047 is 74039818.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81893047 - 2¹⁵ = 81860279 is a prime.

It is a super-2 number, since 2×81893047² = 13412942293888418, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81893057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40946523 + 40946524.

It is an arithmetic number, because the mean of its divisors is an integer number (40946524).

Almost surely, 2^81893047 is an apocalyptic number.

81893047 is a deficient number, since it is larger than the sum of its proper divisors (1).

81893047 is an equidigital number, since it uses as much as digits as its factorization.

81893047 is an odious number, because the sum of its binary digits is odd.

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

The square root of 81893047 is about 9049.4777197361. The cubic root of 81893047 is about 434.2591821166.

It can be divided in two parts, 8189 and 3047, that added together give a square (11236 = 106²).

The spelling of 81893047 in words is "eighty-one million, eight hundred ninety-three thousand, forty-seven".