19916945 has 8 divisors (see below), whose sum is σ = 25306344. Its totient is φ = 14996224.

The previous prime is 19916933. The next prime is 19916947. The reversal of 19916945 is 54961991.

It can be written as a sum of positive squares in 4 ways, for example, as 6130576 + 13786369 = 2476^2 + 3713^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 19916945 - 2¹⁸ = 19654801 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19916896 and 19916905.

It is not an unprimeable number, because it can be changed into a prime (19916947) 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 7 ways as a sum of consecutive naturals, for example, 117074 + ... + 117243.

It is an arithmetic number, because the mean of its divisors is an integer number (3163293).

Almost surely, 2^19916945 is an apocalyptic number.

It is an amenable number.

19916945 is a deficient number, since it is larger than the sum of its proper divisors (5389399).

19916945 is a wasteful number, since it uses less digits than its factorization.

19916945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234339.

The product of its digits is 87480, while the sum is 44.

The square root of 19916945 is about 4462.8404632028. The cubic root of 19916945 is about 271.0654970750.

The spelling of 19916945 in words is "nineteen million, nine hundred sixteen thousand, nine hundred forty-five".