81247429 has 2 divisors, whose sum is σ = 81247430. Its totient is φ = 81247428.

The previous prime is 81247427. The next prime is 81247433. The reversal of 81247429 is 92474218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53684929 + 27562500 = 7327^2 + 5250^2 .

It is a cyclic number.

It is not a de Polignac number, because 81247429 - 2¹ = 81247427 is a prime.

It is a super-2 number, since 2×81247429² = 13202289438220082, which contains 22 as substring.

Together with 81247427, it forms a pair of twin primes.

It is a congruent number.

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, 40623714 + 40623715.

It is an arithmetic number, because the mean of its divisors is an integer number (40623715).

Almost surely, 2^81247429 is an apocalyptic number.

It is an amenable number.

81247429 is a deficient number, since it is larger than the sum of its proper divisors (1).

81247429 is an equidigital number, since it uses as much as digits as its factorization.

81247429 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32256, while the sum is 37.

The square root of 81247429 is about 9013.7355741113. The cubic root of 81247429 is about 433.1149842105.

The spelling of 81247429 in words is "eighty-one million, two hundred forty-seven thousand, four hundred twenty-nine".