81052057 has 4 divisors (see below), whose sum is σ = 81520740. Its totient is φ = 80583376.

The previous prime is 81052021. The next prime is 81052061. The reversal of 81052057 is 75025018.

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

It can be written as a sum of positive squares in 2 ways, for example, as 48664576 + 32387481 = 6976^2 + 5691^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81052057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81052007) 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, 234082 + ... + 234427.

It is an arithmetic number, because the mean of its divisors is an integer number (20380185).

Almost surely, 2^81052057 is an apocalyptic number.

It is an amenable number.

81052057 is a deficient number, since it is larger than the sum of its proper divisors (468683).

81052057 is a wasteful number, since it uses less digits than its factorization.

81052057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468682.

The product of its (nonzero) digits is 2800, while the sum is 28.

The square root of 81052057 is about 9002.8915910390. The cubic root of 81052057 is about 432.7675415955.

The spelling of 81052057 in words is "eighty-one million, fifty-two thousand, fifty-seven".