81575101 has 2 divisors, whose sum is σ = 81575102. Its totient is φ = 81575100.

The previous prime is 81575099. The next prime is 81575107. The reversal of 81575101 is 10157518.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77968900 + 3606201 = 8830^2 + 1899^2 .

It is a cyclic number.

It is not a de Polignac number, because 81575101 - 2¹ = 81575099 is a prime.

Together with 81575099, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81575101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81575107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40787550 + 40787551.

It is an arithmetic number, because the mean of its divisors is an integer number (40787551).

Almost surely, 2^81575101 is an apocalyptic number.

It is an amenable number.

81575101 is a deficient number, since it is larger than the sum of its proper divisors (1).

81575101 is an equidigital number, since it uses as much as digits as its factorization.

81575101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1400, while the sum is 28.

The square root of 81575101 is about 9031.8935445454. The cubic root of 81575101 is about 433.6964561135.

The spelling of 81575101 in words is "eighty-one million, five hundred seventy-five thousand, one hundred one".