81942473 has 2 divisors, whose sum is σ = 81942474. Its totient is φ = 81942472.

The previous prime is 81942463. The next prime is 81942481. The reversal of 81942473 is 37424918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71098624 + 10843849 = 8432^2 + 3293^2 .

It is a cyclic number.

It is not a de Polignac number, because 81942473 - 2¹⁰ = 81941449 is a prime.

It is equal to p_4776248 and since 81942473 and 4776248 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (81942463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40971236 + 40971237.

It is an arithmetic number, because the mean of its divisors is an integer number (40971237).

Almost surely, 2^81942473 is an apocalyptic number.

It is an amenable number.

81942473 is a deficient number, since it is larger than the sum of its proper divisors (1).

81942473 is an equidigital number, since it uses as much as digits as its factorization.

81942473 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 38.

The square root of 81942473 is about 9052.2081836423. The cubic root of 81942473 is about 434.3465292866.

The spelling of 81942473 in words is "eighty-one million, nine hundred forty-two thousand, four hundred seventy-three".