19941981 has 8 divisors (see below), whose sum is σ = 27207840. Its totient is φ = 12985392.

The previous prime is 19941973. The next prime is 19941991. The reversal of 19941981 is 18914991.

It is a happy number.

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

It is not a de Polignac number, because 19941981 - 2³ = 19941973 is a prime.

It is a super-2 number, since 2×19941981² = 795365212408722, 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 (19941931) 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, 77166 + ... + 77423.

It is an arithmetic number, because the mean of its divisors is an integer number (3400980).

Almost surely, 2^19941981 is an apocalyptic number.

It is an amenable number.

19941981 is a deficient number, since it is larger than the sum of its proper divisors (7265859).

19941981 is a wasteful number, since it uses less digits than its factorization.

19941981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154635.

The product of its digits is 23328, while the sum is 42.

The square root of 19941981 is about 4465.6445223506. The cubic root of 19941981 is about 271.1790277767.

The spelling of 19941981 in words is "nineteen million, nine hundred forty-one thousand, nine hundred eighty-one".