19972581 has 8 divisors (see below), whose sum is σ = 26995200. Its totient is φ = 13132512.

The previous prime is 19972567. The next prime is 19972613. The reversal of 19972581 is 18527991.

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

It is not a de Polignac number, because 19972581 - 2¹³ = 19964389 is a prime.

It is a super-2 number, since 2×19972581² = 797807983603122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19972541) 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, 45381 + ... + 45818.

It is an arithmetic number, because the mean of its divisors is an integer number (3374400).

Almost surely, 2^19972581 is an apocalyptic number.

It is an amenable number.

19972581 is a deficient number, since it is larger than the sum of its proper divisors (7022619).

19972581 is an equidigital number, since it uses as much as digits as its factorization.

19972581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91275.

The product of its digits is 45360, while the sum is 42.

The square root of 19972581 is about 4469.0693662104. The cubic root of 19972581 is about 271.3176605690.

The spelling of 19972581 in words is "nineteen million, nine hundred seventy-two thousand, five hundred eighty-one".