87031391 has 4 divisors (see below), whose sum is σ = 87074400. Its totient is φ = 86988384.

The previous prime is 87031369. The next prime is 87031423. The reversal of 87031391 is 19313078.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19313078 = 2 ⋅9656539.

It is a cyclic number.

It is not a de Polignac number, because 87031391 - 2⁶ = 87031327 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87031331) 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, 18311 + ... + 22568.

It is an arithmetic number, because the mean of its divisors is an integer number (21768600).

Almost surely, 2^87031391 is an apocalyptic number.

87031391 is a deficient number, since it is larger than the sum of its proper divisors (43009).

87031391 is a wasteful number, since it uses less digits than its factorization.

87031391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43008.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 87031391 is about 9329.0616355559. The cubic root of 87031391 is about 443.1580488705.

The spelling of 87031391 in words is "eighty-seven million, thirty-one thousand, three hundred ninety-one".