19453981 has 4 divisors (see below), whose sum is σ = 19463392. Its totient is φ = 19444572.

The previous prime is 19453979. The next prime is 19454003. The reversal of 19453981 is 18935491.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 19453981 - 2¹ = 19453979 is a prime.

It is a super-2 number, since 2×19453981² = 756914753496722, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 12.

It is a zygodrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19453901) 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 3 ways as a sum of consecutive naturals, for example, 105 + ... + 6238.

It is an arithmetic number, because the mean of its divisors is an integer number (4865848).

Almost surely, 2^19453981 is an apocalyptic number.

It is an amenable number.

19453981 is a deficient number, since it is larger than the sum of its proper divisors (9411).

19453981 is an equidigital number, since it uses as much as digits as its factorization.

19453981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9410.

The product of its digits is 38880, while the sum is 40.

The square root of 19453981 is about 4410.6667296453. Note that the first 3 decimals coincide. The cubic root of 19453981 is about 268.9487287293.

The spelling of 19453981 in words is "nineteen million, four hundred fifty-three thousand, nine hundred eighty-one".