81970573 has 2 divisors, whose sum is σ = 81970574. Its totient is φ = 81970572.

The previous prime is 81970571. The next prime is 81970639. The reversal of 81970573 is 37507918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67930564 + 14040009 = 8242^2 + 3747^2 .

It is a cyclic number.

It is not a de Polignac number, because 81970573 - 2¹ = 81970571 is a prime.

Together with 81970571, 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 (81970571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40985286 + 40985287.

It is an arithmetic number, because the mean of its divisors is an integer number (40985287).

Almost surely, 2^81970573 is an apocalyptic number.

It is an amenable number.

81970573 is a deficient number, since it is larger than the sum of its proper divisors (1).

81970573 is an equidigital number, since it uses as much as digits as its factorization.

81970573 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52920, while the sum is 40.

The square root of 81970573 is about 9053.7601580780. The cubic root of 81970573 is about 434.3961728237.

The spelling of 81970573 in words is "eighty-one million, nine hundred seventy thousand, five hundred seventy-three".