21101100101001 has 8 divisors (see below), whose sum is σ = 31260889038560. Its totient is φ = 14067400067316.

The previous prime is 21101100100961. The next prime is 21101100101041. The reversal of 21101100101001 is 10010100110112.

It is an interprime number because it is at equal distance from previous prime (21101100100961) and next prime (21101100101041).

It is a de Polignac number, because none of the positive numbers 2^k-21101100101001 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21101100101041) 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, 390761112955 + ... + 390761113008.

It is an arithmetic number, because the mean of its divisors is an integer number (3907611129820).

Almost surely, 2^{21101100101001} is an apocalyptic number.

It is an amenable number.

21101100101001 is a deficient number, since it is larger than the sum of its proper divisors (10159788937559).

21101100101001 is an equidigital number, since it uses as much as digits as its factorization.

21101100101001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 781522225972 (or 781522225966 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

Adding to 21101100101001 its reverse (10010100110112), we get a palindrome (31111200211113).

The spelling of 21101100101001 in words is "twenty-one trillion, one hundred one billion, one hundred million, one hundred one thousand, one".