81951473 has 2 divisors, whose sum is σ = 81951474. Its totient is φ = 81951472.

The previous prime is 81951451. The next prime is 81951491. The reversal of 81951473 is 37415918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81938704 + 12769 = 9052^2 + 113^2 .

It is a cyclic number.

It is not a de Polignac number, because 81951473 - 2⁸ = 81951217 is a prime.

It is not a weakly prime, because it can be changed into another prime (81951403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40975736 + 40975737.

It is an arithmetic number, because the mean of its divisors is an integer number (40975737).

Almost surely, 2^81951473 is an apocalyptic number.

It is an amenable number.

81951473 is a deficient number, since it is larger than the sum of its proper divisors (1).

81951473 is an equidigital number, since it uses as much as digits as its factorization.

81951473 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30240, while the sum is 38.

The square root of 81951473 is about 9052.7052862666. The cubic root of 81951473 is about 434.3624305871.

The spelling of 81951473 in words is "eighty-one million, nine hundred fifty-one thousand, four hundred seventy-three".