21123212210100 has 1728 divisors, whose sum is σ = 91933690867200. Its totient is φ = 3914724556800.

The previous prime is 21123212210099. The next prime is 21123212210141. The reversal of 21123212210100 is 101221232112.

21123212210100 is a `hidden beast` number, since 2 + 112 + 321 + 221 + 0 + 10 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 575 ways as a sum of consecutive naturals, for example, 4966659574 + ... + 4966663826.

It is an arithmetic number, because the mean of its divisors is an integer number (53202367400).

Almost surely, 2^{21123212210100} is an apocalyptic number.

21123212210100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21123212210100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45966845433600).

21123212210100 is an abundant number, since it is smaller than the sum of its proper divisors (70810478657100).

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

21123212210100 is a wasteful number, since it uses less digits than its factorization.

21123212210100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4490 (or 4480 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 21123212210100 its reverse (101221232112), we get a palindrome (21224433442212).

It can be divided in two parts, 21123212 and 210100, that added together give a palindrome (21333312).

The spelling of 21123212210100 in words is "twenty-one trillion, one hundred twenty-three billion, two hundred twelve million, two hundred ten thousand, one hundred".