21230101 has 4 divisors (see below), whose sum is σ = 21418092. Its totient is φ = 21042112.

The previous prime is 21230047. The next prime is 21230123. The reversal of 21230101 is 10103212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9771876 + 11458225 = 3126^2 + 3385^2 .

It is a cyclic number.

It is not a de Polignac number, because 21230101 - 2⁹ = 21229589 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230141) 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, 93826 + ... + 94051.

It is an arithmetic number, because the mean of its divisors is an integer number (5354523).

Almost surely, 2^21230101 is an apocalyptic number.

It is an amenable number.

21230101 is a deficient number, since it is larger than the sum of its proper divisors (187991).

21230101 is a wasteful number, since it uses less digits than its factorization.

21230101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187990.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21230101 is about 4607.6133735373. The cubic root of 21230101 is about 276.8964280644.

Adding to 21230101 its reverse (10103212), we get a palindrome (31333313).

The spelling of 21230101 in words is "twenty-one million, two hundred thirty thousand, one hundred one".