81435437 has 2 divisors, whose sum is σ = 81435438. Its totient is φ = 81435436.

The previous prime is 81435413. The next prime is 81435439. The reversal of 81435437 is 73453418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80748196 + 687241 = 8986^2 + 829^2 .

It is a cyclic number.

It is not a de Polignac number, because 81435437 - 2⁸ = 81435181 is a prime.

Together with 81435439, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 81435397 and 81435406.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81435439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40717718 + 40717719.

It is an arithmetic number, because the mean of its divisors is an integer number (40717719).

Almost surely, 2^81435437 is an apocalyptic number.

It is an amenable number.

81435437 is a deficient number, since it is larger than the sum of its proper divisors (1).

81435437 is an equidigital number, since it uses as much as digits as its factorization.

81435437 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40320, while the sum is 35.

The square root of 81435437 is about 9024.1585203275. The cubic root of 81435437 is about 433.4488054531.

The spelling of 81435437 in words is "eighty-one million, four hundred thirty-five thousand, four hundred thirty-seven".