87169021 has 2 divisors, whose sum is σ = 87169022. Its totient is φ = 87169020.

The previous prime is 87169009. The next prime is 87169073. The reversal of 87169021 is 12096178.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77246521 + 9922500 = 8789^2 + 3150^2 .

It is a cyclic number.

It is not a de Polignac number, because 87169021 - 2⁵ = 87168989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87169721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43584510 + 43584511.

It is an arithmetic number, because the mean of its divisors is an integer number (43584511).

Almost surely, 2^87169021 is an apocalyptic number.

It is an amenable number.

87169021 is a deficient number, since it is larger than the sum of its proper divisors (1).

87169021 is an equidigital number, since it uses as much as digits as its factorization.

87169021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 87169021 is about 9336.4351333900. The cubic root of 87169021 is about 443.3915267735.

The spelling of 87169021 in words is "eighty-seven million, one hundred sixty-nine thousand, twenty-one".