16518491 has 4 divisors (see below), whose sum is σ = 18020184. Its totient is φ = 15016800.

The previous prime is 16518473. The next prime is 16518499. The reversal of 16518491 is 19481561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19481561 = 11 ⋅1771051.

It is a cyclic number.

It is not a de Polignac number, because 16518491 - 2¹⁰ = 16517467 is a prime.

It is a super-3 number, since 3×16518491³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16518499) 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, 750830 + ... + 750851.

It is an arithmetic number, because the mean of its divisors is an integer number (4505046).

Almost surely, 2^16518491 is an apocalyptic number.

16518491 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

16518491 is a deficient number, since it is larger than the sum of its proper divisors (1501693).

16518491 is a wasteful number, since it uses less digits than its factorization.

16518491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1501692.

The product of its digits is 8640, while the sum is 35.

The square root of 16518491 is about 4064.2946497517. The cubic root of 16518491 is about 254.6772335631.

The spelling of 16518491 in words is "sixteen million, five hundred eighteen thousand, four hundred ninety-one".