20197818201816 has 128 divisors (see below), whose sum is σ = 59608099454400. Its totient is φ = 6314943559680.

The previous prime is 20197818201797. The next prime is 20197818201817. The reversal of 20197818201816 is 61810281879102.

It is a super-2 number, since 2×20197818201816² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20197818201817) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8310615 + ... + 10462406.

Almost surely, 2^{20197818201816} is an apocalyptic number.

It is an amenable number.

20197818201816 is an abundant number, since it is smaller than the sum of its proper divisors (39410281252584).

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

20197818201816 is a wasteful number, since it uses less digits than its factorization.

20197818201816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18773346 (or 18773336 counting only the distinct ones).

The product of its (nonzero) digits is 774144, while the sum is 54.

The spelling of 20197818201816 in words is "twenty trillion, one hundred ninety-seven billion, eight hundred eighteen million, two hundred one thousand, eight hundred sixteen".