81247433 has 2 divisors, whose sum is σ = 81247434. Its totient is φ = 81247432.

The previous prime is 81247429. The next prime is 81247457. The reversal of 81247433 is 33474218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77299264 + 3948169 = 8792^2 + 1987^2 .

It is a cyclic number.

It is not a de Polignac number, because 81247433 - 2² = 81247429 is a prime.

It is a super-2 number, since 2×81247433² = 13202290738178978, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81247433.

It is not a weakly prime, because it can be changed into another prime (81247423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40623716 + 40623717.

It is an arithmetic number, because the mean of its divisors is an integer number (40623717).

Almost surely, 2^81247433 is an apocalyptic number.

It is an amenable number.

81247433 is a deficient number, since it is larger than the sum of its proper divisors (1).

81247433 is an equidigital number, since it uses as much as digits as its factorization.

81247433 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 32.

The square root of 81247433 is about 9013.7357959949. The cubic root of 81247433 is about 433.1149913182.

The spelling of 81247433 in words is "eighty-one million, two hundred forty-seven thousand, four hundred thirty-three".