19891081 has 16 divisors (see below), whose sum is σ = 24053760. Its totient is φ = 16068240.

The previous prime is 19891073. The next prime is 19891099. The reversal of 19891081 is 18019891.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 19891081 - 2³ = 19891073 is a prime.

It is a super-2 number, since 2×19891081² = 791310206697122, 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 19891081.

It is not an unprimeable number, because it can be changed into a prime (19891031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45936 + ... + 46366.

It is an arithmetic number, because the mean of its divisors is an integer number (1503360).

Almost surely, 2^19891081 is an apocalyptic number.

It is an amenable number.

19891081 is a deficient number, since it is larger than the sum of its proper divisors (4162679).

19891081 is a wasteful number, since it uses less digits than its factorization.

19891081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 804.

The product of its (nonzero) digits is 5184, while the sum is 37.

The square root of 19891081 is about 4459.9418157640. The cubic root of 19891081 is about 270.9481116870.

The spelling of 19891081 in words is "nineteen million, eight hundred ninety-one thousand, eighty-one".