19913845 has 12 divisors (see below), whose sum is σ = 27798444. Its totient is φ = 13655040.

The previous prime is 19913779. The next prime is 19913863. The reversal of 19913845 is 54831991.

It can be written as a sum of positive squares in 2 ways, for example, as 14447601 + 5466244 = 3801^2 + 2338^2 .

It is not a de Polignac number, because 19913845 - 2¹³ = 19905653 is a prime.

It is a super-2 number, since 2×19913845² = 793122445368050, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19913798 and 19913807.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 40396 + ... + 40885.

It is an arithmetic number, because the mean of its divisors is an integer number (2316537).

Almost surely, 2^19913845 is an apocalyptic number.

It is an amenable number.

19913845 is a deficient number, since it is larger than the sum of its proper divisors (7884599).

19913845 is an equidigital number, since it uses as much as digits as its factorization.

19913845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81300 (or 81293 counting only the distinct ones).

The product of its digits is 38880, while the sum is 40.

The square root of 19913845 is about 4462.4931372496. The cubic root of 19913845 is about 271.0514328926.

The spelling of 19913845 in words is "nineteen million, nine hundred thirteen thousand, eight hundred forty-five".