21318101 has 4 divisors (see below), whose sum is σ = 24363552. Its totient is φ = 18272652.

The previous prime is 21318091. The next prime is 21318109. The reversal of 21318101 is 10181312.

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 21318101 - 2²² = 17123797 is a prime.

It is a super-2 number, since 2×21318101² = 908922860492402, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21318101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21318109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1522715 + ... + 1522728.

It is an arithmetic number, because the mean of its divisors is an integer number (6090888).

Almost surely, 2^21318101 is an apocalyptic number.

It is an amenable number.

21318101 is a deficient number, since it is larger than the sum of its proper divisors (3045451).

21318101 is an equidigital number, since it uses as much as digits as its factorization.

21318101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3045450.

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 21318101 is about 4617.1529106149. The cubic root of 21318101 is about 277.2784845856.

Adding to 21318101 its reverse (10181312), we get a palindrome (31499413).

The spelling of 21318101 in words is "twenty-one million, three hundred eighteen thousand, one hundred one".