216991503 has 12 divisors (see below), whose sum is σ = 313583400. Its totient is φ = 144591216.

The previous prime is 216991501. The next prime is 216991513. The reversal of 216991503 is 305199612.

216991503 is a `hidden beast` number, since 2 + 1 + 69 + 91 + 503 = 666.

It is not a de Polignac number, because 216991503 - 2¹ = 216991501 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216991501) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19825 + ... + 28757.

It is an arithmetic number, because the mean of its divisors is an integer number (26131950).

Almost surely, 2^216991503 is an apocalyptic number.

216991503 is a deficient number, since it is larger than the sum of its proper divisors (96591897).

216991503 is a wasteful number, since it uses less digits than its factorization.

216991503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11638 (or 11635 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 36.

The square root of 216991503 is about 14730.6314528604. The cubic root of 216991503 is about 600.9166571862.

The spelling of 216991503 in words is "two hundred sixteen million, nine hundred ninety-one thousand, five hundred three".