21100122121 has 8 divisors (see below), whose sum is σ = 22935576384. Its totient is φ = 19295006160.

The previous prime is 21100122107. The next prime is 21100122133. The reversal of 21100122121 is 12122100112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21100122121 - 2⁵ = 21100122089 is a prime.

It is a super-2 number, since 2×21100122121² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21100122221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7583125 + ... + 7585906.

It is an arithmetic number, because the mean of its divisors is an integer number (2866947048).

Almost surely, 2^21100122121 is an apocalyptic number.

It is an amenable number.

21100122121 is a deficient number, since it is larger than the sum of its proper divisors (1835454263).

21100122121 is a wasteful number, since it uses less digits than its factorization.

21100122121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15169151.

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

Adding to 21100122121 its reverse (12122100112), we get a palindrome (33222222233).

The spelling of 21100122121 in words is "twenty-one billion, one hundred million, one hundred twenty-two thousand, one hundred twenty-one".