87099821 has 2 divisors, whose sum is σ = 87099822. Its totient is φ = 87099820.

The previous prime is 87099809. The next prime is 87099833. The reversal of 87099821 is 12899078.

It is a balanced prime because it is at equal distance from previous prime (87099809) and next prime (87099833).

It can be written as a sum of positive squares in only one way, i.e., 58690921 + 28408900 = 7661^2 + 5330^2 .

It is a cyclic number.

It is not a de Polignac number, because 87099821 - 2¹⁰ = 87098797 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87099841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43549910 + 43549911.

It is an arithmetic number, because the mean of its divisors is an integer number (43549911).

Almost surely, 2^87099821 is an apocalyptic number.

It is an amenable number.

87099821 is a deficient number, since it is larger than the sum of its proper divisors (1).

87099821 is an equidigital number, since it uses as much as digits as its factorization.

87099821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 87099821 is about 9332.7284863538. The cubic root of 87099821 is about 443.2741654443.

The spelling of 87099821 in words is "eighty-seven million, ninety-nine thousand, eight hundred twenty-one".