20491019818 has 16 divisors (see below), whose sum is σ = 31086815040. Its totient is φ = 10129392000.

The previous prime is 20491019771. The next prime is 20491019833. The reversal of 20491019818 is 81891019402.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97063 + ... + 224506.

It is an arithmetic number, because the mean of its divisors is an integer number (1942925940).

Almost surely, 2^20491019818 is an apocalyptic number.

20491019818 is a deficient number, since it is larger than the sum of its proper divisors (10595795222).

20491019818 is a wasteful number, since it uses less digits than its factorization.

20491019818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321933.

The product of its (nonzero) digits is 41472, while the sum is 43.

The spelling of 20491019818 in words is "twenty billion, four hundred ninety-one million, nineteen thousand, eight hundred eighteen".