21818198197620 has 144 divisors (see below), whose sum is σ = 75337462392192. Its totient is φ = 5059292325120.

The previous prime is 21818198197561. The next prime is 21818198197639. The reversal of 21818198197620 is 2679189181812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 239504287 + ... + 239595366.

It is an arithmetic number, because the mean of its divisors is an integer number (523176822168).

Almost surely, 2^{21818198197620} is an apocalyptic number.

21818198197620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21818198197620 is an abundant number, since it is smaller than the sum of its proper divisors (53519264194572).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21818198197620 is a wasteful number, since it uses less digits than its factorization.

21818198197620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 479099702 (or 479099697 counting only the distinct ones).

The product of its (nonzero) digits is 6967296, while the sum is 63.

The spelling of 21818198197620 in words is "twenty-one trillion, eight hundred eighteen billion, one hundred ninety-eight million, one hundred ninety-seven thousand, six hundred twenty".