19105981 has 4 divisors (see below), whose sum is σ = 19152000. Its totient is φ = 19059964.

The previous prime is 19105979. The next prime is 19105991. The reversal of 19105981 is 18950191.

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.

It is a cyclic number.

It is not a de Polignac number, because 19105981 - 2¹ = 19105979 is a prime.

It is a super-2 number, since 2×19105981² = 730077019944722, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19105991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22381 + ... + 23218.

It is an arithmetic number, because the mean of its divisors is an integer number (4788000).

Almost surely, 2^19105981 is an apocalyptic number.

It is an amenable number.

19105981 is a deficient number, since it is larger than the sum of its proper divisors (46019).

19105981 is an equidigital number, since it uses as much as digits as its factorization.

19105981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46018.

The product of its (nonzero) digits is 3240, while the sum is 34.

The square root of 19105981 is about 4371.0388925289. The cubic root of 19105981 is about 267.3353853709.

The spelling of 19105981 in words is "nineteen million, one hundred five thousand, nine hundred eighty-one".