81071051 has 4 divisors (see below), whose sum is σ = 81090792. Its totient is φ = 81051312.

The previous prime is 81071017. The next prime is 81071057. The reversal of 81071051 is 15017018.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81071051 - 2¹⁰ = 81070027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81071057) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1130 + ... + 12783.

It is an arithmetic number, because the mean of its divisors is an integer number (20272698).

Almost surely, 2^81071051 is an apocalyptic number.

81071051 is a deficient number, since it is larger than the sum of its proper divisors (19741).

81071051 is a wasteful number, since it uses less digits than its factorization.

81071051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19740.

The product of its (nonzero) digits is 280, while the sum is 23.

The square root of 81071051 is about 9003.9464125460. The cubic root of 81071051 is about 432.8013443349.

Adding to 81071051 its reverse (15017018), we get a palindrome (96088069).

The spelling of 81071051 in words is "eighty-one million, seventy-one thousand, fifty-one".