16217681 has 8 divisors (see below), whose sum is σ = 16800000. Its totient is φ = 15639120.

The previous prime is 16217651. The next prime is 16217683. The reversal of 16217681 is 18671261.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 16217681 - 2²² = 12023377 is a prime.

It is a super-2 number, since 2×16217681² = 526026354035522, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (16217683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10070 + ... + 11568.

It is an arithmetic number, because the mean of its divisors is an integer number (2100000).

Almost surely, 2^16217681 is an apocalyptic number.

It is an amenable number.

16217681 is a deficient number, since it is larger than the sum of its proper divisors (582319).

16217681 is a wasteful number, since it uses less digits than its factorization.

16217681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1879.

The product of its digits is 4032, while the sum is 32.

The square root of 16217681 is about 4027.1182004009. The cubic root of 16217681 is about 253.1218200281.

The spelling of 16217681 in words is "sixteen million, two hundred seventeen thousand, six hundred eighty-one".