19654021805 has 16 divisors (see below), whose sum is σ = 25812730944. Its totient is φ = 14247262080.

The previous prime is 19654021789. The next prime is 19654021811. The reversal of 19654021805 is 50812045691.

It is not a de Polignac number, because 19654021805 - 2⁴ = 19654021789 is a prime.

It is a super-2 number, since 2×19654021805² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 565112 + ... + 598881.

It is an arithmetic number, because the mean of its divisors is an integer number (1613295684).

Almost surely, 2^19654021805 is an apocalyptic number.

It is an amenable number.

19654021805 is a deficient number, since it is larger than the sum of its proper divisors (6158709139).

19654021805 is a wasteful number, since it uses less digits than its factorization.

19654021805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1164316.

The product of its (nonzero) digits is 86400, while the sum is 41.

The spelling of 19654021805 in words is "nineteen billion, six hundred fifty-four million, twenty-one thousand, eight hundred five".