21857810164212 has 48 divisors (see below), whose sum is σ = 56400227497152. Its totient is φ = 6532844878080.

The previous prime is 21857810164199. The next prime is 21857810164231. The reversal of 21857810164212 is 21246101875812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1134164823 + ... + 1134184094.

It is an arithmetic number, because the mean of its divisors is an integer number (1175004739524).

Almost surely, 2^{21857810164212} is an apocalyptic number.

21857810164212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21857810164212 is an abundant number, since it is smaller than the sum of its proper divisors (34542417332940).

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

21857810164212 is a wasteful number, since it uses less digits than its factorization.

21857810164212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2268349008 (or 2268349006 counting only the distinct ones).

The product of its (nonzero) digits is 430080, while the sum is 48.

It can be divided in two parts, 21857810 and 164212, that added together give a palindrome (22022022).

The spelling of 21857810164212 in words is "twenty-one trillion, eight hundred fifty-seven billion, eight hundred ten million, one hundred sixty-four thousand, two hundred twelve".