19945581 has 8 divisors (see below), whose sum is σ = 26857824. Its totient is φ = 13165200.

The previous prime is 19945579. The next prime is 19945589. The reversal of 19945581 is 18554991.

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

It is not a de Polignac number, because 19945581 - 2¹ = 19945579 is a prime.

It is a super-2 number, since 2×19945581² = 795652402855122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19945589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32611 + ... + 33216.

It is an arithmetic number, because the mean of its divisors is an integer number (3357228).

Almost surely, 2^19945581 is an apocalyptic number.

It is an amenable number.

19945581 is a deficient number, since it is larger than the sum of its proper divisors (6912243).

19945581 is a wasteful number, since it uses less digits than its factorization.

19945581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65931.

The product of its digits is 64800, while the sum is 42.

The square root of 19945581 is about 4466.0475814751. The cubic root of 19945581 is about 271.1953448745.

The spelling of 19945581 in words is "nineteen million, nine hundred forty-five thousand, five hundred eighty-one".