87509581 has 4 divisors (see below), whose sum is σ = 87579072. Its totient is φ = 87440092.

The previous prime is 87509537. The next prime is 87509593. The reversal of 87509581 is 18590578.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 87509581 - 2⁷ = 87509453 is a prime.

It is a super-2 number, since 2×87509581² = 15315853533591122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87509281) 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, 32821 + ... + 35386.

It is an arithmetic number, because the mean of its divisors is an integer number (21894768).

Almost surely, 2^87509581 is an apocalyptic number.

It is an amenable number.

87509581 is a deficient number, since it is larger than the sum of its proper divisors (69491).

87509581 is a wasteful number, since it uses less digits than its factorization.

87509581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69490.

The product of its (nonzero) digits is 100800, while the sum is 43.

The square root of 87509581 is about 9354.6555789083. The cubic root of 87509581 is about 443.9682041051.

The spelling of 87509581 in words is "eighty-seven million, five hundred nine thousand, five hundred eighty-one".