87821081 has 2 divisors, whose sum is σ = 87821082. Its totient is φ = 87821080.

The previous prime is 87821033. The next prime is 87821101. The reversal of 87821081 is 18012878.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76825225 + 10995856 = 8765^2 + 3316^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87821081 is a prime.

It is a super-2 number, since 2×87821081² = 15425084536017122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (87821011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43910540 + 43910541.

It is an arithmetic number, because the mean of its divisors is an integer number (43910541).

Almost surely, 2^87821081 is an apocalyptic number.

It is an amenable number.

87821081 is a deficient number, since it is larger than the sum of its proper divisors (1).

87821081 is an equidigital number, since it uses as much as digits as its factorization.

87821081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7168, while the sum is 35.

The square root of 87821081 is about 9371.2902526813. The cubic root of 87821081 is about 444.4943648765.

The spelling of 87821081 in words is "eighty-seven million, eight hundred twenty-one thousand, eighty-one".