21003565101 has 4 divisors (see below), whose sum is σ = 28004753472. Its totient is φ = 14002376732.

The previous prime is 21003565097. The next prime is 21003565139. The reversal of 21003565101 is 10156530012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21003565101 - 2² = 21003565097 is a prime.

It is a super-2 number, since 2×21003565101² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003565171) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3500594181 + ... + 3500594186.

It is an arithmetic number, because the mean of its divisors is an integer number (7001188368).

Almost surely, 2^21003565101 is an apocalyptic number.

It is an amenable number.

21003565101 is a deficient number, since it is larger than the sum of its proper divisors (7001188371).

21003565101 is an equidigital number, since it uses as much as digits as its factorization.

21003565101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7001188370.

The product of its (nonzero) digits is 900, while the sum is 24.

The spelling of 21003565101 in words is "twenty-one billion, three million, five hundred sixty-five thousand, one hundred one".