16463981 has 4 divisors (see below), whose sum is σ = 16473372. Its totient is φ = 16454592.

The previous prime is 16463971. The next prime is 16463989. The reversal of 16463981 is 18936461.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18936461 = 109 ⋅173729.

It can be written as a sum of positive squares in 2 ways, for example, as 12888100 + 3575881 = 3590^2 + 1891^2 .

It is a cyclic number.

It is not a de Polignac number, because 16463981 - 2⁶ = 16463917 is a prime.

It is a super-2 number, since 2×16463981² = 542125340736722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16463989) 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, 1196 + ... + 5861.

It is an arithmetic number, because the mean of its divisors is an integer number (4118343).

Almost surely, 2^16463981 is an apocalyptic number.

It is an amenable number.

16463981 is a deficient number, since it is larger than the sum of its proper divisors (9391).

16463981 is an equidigital number, since it uses as much as digits as its factorization.

16463981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9390.

The product of its digits is 31104, while the sum is 38.

The square root of 16463981 is about 4057.5831476385. The cubic root of 16463981 is about 254.3967851357.

The spelling of 16463981 in words is "sixteen million, four hundred sixty-three thousand, nine hundred eighty-one".