21102101001 has 48 divisors (see below), whose sum is σ = 31231957120. Its totient is φ = 13726817280.

The previous prime is 21102100951. The next prime is 21102101029. The reversal of 21102101001 is 10010120112.

It is a happy number.

It is not a de Polignac number, because 21102101001 - 2¹⁷ = 21101969929 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 (21102101101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 29762835 + ... + 29763543.

Almost surely, 2^21102101001 is an apocalyptic number.

It is an amenable number.

21102101001 is a deficient number, since it is larger than the sum of its proper divisors (10129856119).

21102101001 is a wasteful number, since it uses less digits than its factorization.

21102101001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1246 (or 1243 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21102101001 its reverse (10010120112), we get a palindrome (31112221113).

The spelling of 21102101001 in words is "twenty-one billion, one hundred two million, one hundred one thousand, one".