21101220210100 has 18 divisors (see below), whose sum is σ = 45789647856134. Its totient is φ = 8440488084000.

The previous prime is 21101220210097. The next prime is 21101220210121. The reversal of 21101220210100 is 101202210112.

It can be written as a sum of positive squares in 3 ways, for example, as 867111091344 + 20234109118756 = 931188^2 + 4498234^2 .

It is a super-2 number, since 2×21101220210100² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 105506100951 + ... + 105506101150.

Almost surely, 2^{21101220210100} is an apocalyptic number.

21101220210100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101220210100 is an abundant number, since it is smaller than the sum of its proper divisors (24688427646034).

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

21101220210100 is a wasteful number, since it uses less digits than its factorization.

21101220210100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211012202115 (or 211012202108 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21101220210100 its reverse (101202210112), we get a palindrome (21202422420212).

The spelling of 21101220210100 in words is "twenty-one trillion, one hundred one billion, two hundred twenty million, two hundred ten thousand, one hundred".