19809812 has 12 divisors (see below), whose sum is σ = 37818816. Its totient is φ = 9004440.

The previous prime is 19809809. The next prime is 19809821. The reversal of 19809812 is 21890891.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225068 + ... + 225155.

It is an arithmetic number, because the mean of its divisors is an integer number (3151568).

Almost surely, 2^19809812 is an apocalyptic number.

It is an amenable number.

19809812 is a deficient number, since it is larger than the sum of its proper divisors (18009004).

19809812 is a wasteful number, since it uses less digits than its factorization.

19809812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450238 (or 450236 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 19809812 is about 4450.8214972070. The cubic root of 19809812 is about 270.5786037159.

The spelling of 19809812 in words is "nineteen million, eight hundred nine thousand, eight hundred twelve".