90871999 has 4 divisors (see below), whose sum is σ = 90891160. Its totient is φ = 90852840.

The previous prime is 90871981. The next prime is 90872017. The reversal of 90871999 is 99917809.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99917809 = 197 ⋅507197.

It is an interprime number because it is at equal distance from previous prime (90871981) and next prime (90872017).

It is a cyclic number.

It is not a de Polignac number, because 90871999 - 2⁵ = 90871967 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 (90871909) 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, 3364 + ... + 13894.

It is an arithmetic number, because the mean of its divisors is an integer number (22722790).

Almost surely, 2^90871999 is an apocalyptic number.

90871999 is a deficient number, since it is larger than the sum of its proper divisors (19161).

90871999 is a wasteful number, since it uses less digits than its factorization.

90871999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19160.

The product of its (nonzero) digits is 367416, while the sum is 52.

The square root of 90871999 is about 9532.6805778857. The cubic root of 90871999 is about 449.5831514284.

The spelling of 90871999 in words is "ninety million, eight hundred seventy-one thousand, nine hundred ninety-nine".