87317781 has 4 divisors (see below), whose sum is σ = 116423712. Its totient is φ = 58211852.

The previous prime is 87317777. The next prime is 87317801. The reversal of 87317781 is 18771378.

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 87317781 - 2² = 87317777 is a prime.

It is a super-2 number, since 2×87317781² = 15248789757527922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87317701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14552961 + ... + 14552966.

It is an arithmetic number, because the mean of its divisors is an integer number (29105928).

Almost surely, 2^87317781 is an apocalyptic number.

It is an amenable number.

87317781 is a deficient number, since it is larger than the sum of its proper divisors (29105931).

87317781 is a wasteful number, since it uses less digits than its factorization.

87317781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29105930.

The product of its digits is 65856, while the sum is 42.

The square root of 87317781 is about 9344.3983754975. The cubic root of 87317781 is about 443.6436095935.

The spelling of 87317781 in words is "eighty-seven million, three hundred seventeen thousand, seven hundred eighty-one".