21001100231 has 4 divisors (see below), whose sum is σ = 21204994512. Its totient is φ = 20797205952.

The previous prime is 21001100227. The next prime is 21001100249. The reversal of 21001100231 is 13200110012.

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

It is a cyclic number.

It is not a de Polignac number, because 21001100231 - 2² = 21001100227 is a prime.

It is a super-2 number, since 2×21001100231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001100251) 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, 101946986 + ... + 101947191.

It is an arithmetic number, because the mean of its divisors is an integer number (5301248628).

Almost surely, 2^21001100231 is an apocalyptic number.

21001100231 is a deficient number, since it is larger than the sum of its proper divisors (203894281).

21001100231 is a wasteful number, since it uses less digits than its factorization.

21001100231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203894280.

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

Adding to 21001100231 its reverse (13200110012), we get a palindrome (34201210243).

The spelling of 21001100231 in words is "twenty-one billion, one million, one hundred thousand, two hundred thirty-one".