87190813 has 4 divisors (see below), whose sum is σ = 87212700. Its totient is φ = 87168928.

The previous prime is 87190811. The next prime is 87190823. The reversal of 87190813 is 31809178.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31809178 = 2 ⋅15904589.

It can be written as a sum of positive squares in 2 ways, for example, as 71014329 + 16176484 = 8427^2 + 4022^2 .

It is a cyclic number.

It is not a de Polignac number, because 87190813 - 2¹ = 87190811 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 (87190811) 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, 3088 + ... + 13561.

It is an arithmetic number, because the mean of its divisors is an integer number (21803175).

Almost surely, 2^87190813 is an apocalyptic number.

It is an amenable number.

87190813 is a deficient number, since it is larger than the sum of its proper divisors (21887).

87190813 is a wasteful number, since it uses less digits than its factorization.

87190813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21886.

The product of its (nonzero) digits is 12096, while the sum is 37.

The square root of 87190813 is about 9337.6021011821. The cubic root of 87190813 is about 443.4284725560.

The spelling of 87190813 in words is "eighty-seven million, one hundred ninety thousand, eight hundred thirteen".