19942381 has 4 divisors (see below), whose sum is σ = 20992000. Its totient is φ = 18892764.

The previous prime is 19942369. The next prime is 19942397. The reversal of 19942381 is 18324991.

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 an emirpimes, since its reverse is a distinct semiprime: 18324991 = 41 ⋅446951.

It is not a de Polignac number, because 19942381 - 2⁹ = 19941869 is a prime.

It is a super-2 number, since 2×19942381² = 795397119898322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19942381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19942361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 524781 + ... + 524818.

It is an arithmetic number, because the mean of its divisors is an integer number (5248000).

Almost surely, 2^19942381 is an apocalyptic number.

It is an amenable number.

19942381 is a deficient number, since it is larger than the sum of its proper divisors (1049619).

19942381 is a wasteful number, since it uses less digits than its factorization.

19942381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1049618.

The product of its digits is 15552, while the sum is 37.

The square root of 19942381 is about 4465.6893084943. The cubic root of 19942381 is about 271.1808408845.

The spelling of 19942381 in words is "nineteen million, nine hundred forty-two thousand, three hundred eighty-one".