19963813 has 4 divisors (see below), whose sum is σ = 21014560. Its totient is φ = 18913068.

The previous prime is 19963807. The next prime is 19963817. The reversal of 19963813 is 31836991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19963813 - 2⁹ = 19963301 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19963817) 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 3 ways as a sum of consecutive naturals, for example, 525345 + ... + 525382.

It is an arithmetic number, because the mean of its divisors is an integer number (5253640).

Almost surely, 2^19963813 is an apocalyptic number.

It is an amenable number.

19963813 is a deficient number, since it is larger than the sum of its proper divisors (1050747).

19963813 is a wasteful number, since it uses less digits than its factorization.

19963813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1050746.

The product of its digits is 34992, while the sum is 40.

The square root of 19963813 is about 4468.0882936665. The cubic root of 19963813 is about 271.2779517728.

The spelling of 19963813 in words is "nineteen million, nine hundred sixty-three thousand, eight hundred thirteen".