19809413 has 4 divisors (see below), whose sum is σ = 21333228. Its totient is φ = 18285600.

The previous prime is 19809409. The next prime is 19809443. The reversal of 19809413 is 31490891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31490891 = 101 ⋅311791.

It can be written as a sum of positive squares in 2 ways, for example, as 4072324 + 15737089 = 2018^2 + 3967^2 .

It is a cyclic number.

It is not a de Polignac number, because 19809413 - 2² = 19809409 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19809443) 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, 761888 + ... + 761913.

It is an arithmetic number, because the mean of its divisors is an integer number (5333307).

Almost surely, 2^19809413 is an apocalyptic number.

19809413 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

19809413 is a deficient number, since it is larger than the sum of its proper divisors (1523815).

19809413 is a wasteful number, since it uses less digits than its factorization.

19809413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1523814.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 19809413 is about 4450.7766737953. The cubic root of 19809413 is about 270.5767870810.

The spelling of 19809413 in words is "nineteen million, eight hundred nine thousand, four hundred thirteen".