87509491 has 4 divisors (see below), whose sum is σ = 87791184. Its totient is φ = 87227800.

The previous prime is 87509453. The next prime is 87509509. The reversal of 87509491 is 19490578.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19490578 = 2 ⋅9745289.

It is a cyclic number.

It is not a de Polignac number, because 87509491 - 2⁷ = 87509363 is a prime.

It is a super-2 number, since 2×87509491² = 15315822030158162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (87509291) 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, 140380 + ... + 141001.

It is an arithmetic number, because the mean of its divisors is an integer number (21947796).

Almost surely, 2^87509491 is an apocalyptic number.

87509491 is a deficient number, since it is larger than the sum of its proper divisors (281693).

87509491 is a wasteful number, since it uses less digits than its factorization.

87509491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281692.

The product of its (nonzero) digits is 90720, while the sum is 43.

The square root of 87509491 is about 9354.6507684681. The cubic root of 87509491 is about 443.9680519041.

The spelling of 87509491 in words is "eighty-seven million, five hundred nine thousand, four hundred ninety-one".