21213121100203 has 4 divisors (see below), whose sum is σ = 21335740297488. Its totient is φ = 21090501902920.

The previous prime is 21213121100183. The next prime is 21213121100207. The reversal of 21213121100203 is 30200112131212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213121100203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21213121100207) 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, 61309598383 + ... + 61309598728.

It is an arithmetic number, because the mean of its divisors is an integer number (5333935074372).

Almost surely, 2^{21213121100203} is an apocalyptic number.

21213121100203 is a deficient number, since it is larger than the sum of its proper divisors (122619197285).

21213121100203 is a wasteful number, since it uses less digits than its factorization.

21213121100203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122619197284.

The product of its (nonzero) digits is 144, while the sum is 19.

Adding to 21213121100203 its reverse (30200112131212), we get a palindrome (51413233231415).

The spelling of 21213121100203 in words is "twenty-one trillion, two hundred thirteen billion, one hundred twenty-one million, one hundred thousand, two hundred three".