21312101 has 8 divisors (see below), whose sum is σ = 22632984. Its totient is φ = 19998720.

The previous prime is 21312079. The next prime is 21312107. The reversal of 21312101 is 10121312.

It can be written as a sum of positive squares in 4 ways, for example, as 8702500 + 12609601 = 2950^2 + 3551^2 .

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 21312101 - 2¹⁰ = 21311077 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4661 + ... + 8021.

It is an arithmetic number, because the mean of its divisors is an integer number (2829123).

Almost surely, 2^21312101 is an apocalyptic number.

It is an amenable number.

21312101 is a deficient number, since it is larger than the sum of its proper divisors (1320883).

21312101 is a wasteful number, since it uses less digits than its factorization.

21312101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3751.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 21312101 is about 4616.5031138298. The cubic root of 21312101 is about 277.2524687128.

Adding to 21312101 its reverse (10121312), we get a palindrome (31433413).

It can be divided in two parts, 21312 and 101, that multiplied together give a palindrome (2152512).

The spelling of 21312101 in words is "twenty-one million, three hundred twelve thousand, one hundred one".