16428549581 has 4 divisors (see below), whose sum is σ = 16429557792. Its totient is φ = 16427541372.

The previous prime is 16428549563. The next prime is 16428549583. The reversal of 16428549581 is 18594582461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16428549581 - 2¹⁴ = 16428533197 is a prime.

It is a super-2 number, since 2×16428549581² (a number of 21 digits) 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 (16428549583) 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, 479255 + ... + 512388.

It is an arithmetic number, because the mean of its divisors is an integer number (4107389448).

Almost surely, 2^16428549581 is an apocalyptic number.

It is an amenable number.

16428549581 is a deficient number, since it is larger than the sum of its proper divisors (1008211).

16428549581 is an equidigital number, since it uses as much as digits as its factorization.

16428549581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1008210.

The product of its digits is 2764800, while the sum is 53.

The spelling of 16428549581 in words is "sixteen billion, four hundred twenty-eight million, five hundred forty-nine thousand, five hundred eighty-one".