16451581 has 2 divisors, whose sum is σ = 16451582. Its totient is φ = 16451580.

The previous prime is 16451579. The next prime is 16451609. The reversal of 16451581 is 18515461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16240900 + 210681 = 4030^2 + 459^2 .

It is a cyclic number.

It is not a de Polignac number, because 16451581 - 2¹ = 16451579 is a prime.

It is a super-2 number, since 2×16451581² = 541309034799122, which contains 22 as substring.

Together with 16451579, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16451681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8225790 + 8225791.

It is an arithmetic number, because the mean of its divisors is an integer number (8225791).

Almost surely, 2^16451581 is an apocalyptic number.

It is an amenable number.

16451581 is a deficient number, since it is larger than the sum of its proper divisors (1).

16451581 is an equidigital number, since it uses as much as digits as its factorization.

16451581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4800, while the sum is 31.

The square root of 16451581 is about 4056.0548566310. The cubic root of 16451581 is about 254.3329019955.

The spelling of 16451581 in words is "sixteen million, four hundred fifty-one thousand, five hundred eighty-one".