21221202423 has 32 divisors (see below), whose sum is σ = 29583348480. Its totient is φ = 13519215360.

The previous prime is 21221202349. The next prime is 21221202461. The reversal of 21221202423 is 32420212212.

It is not a de Polignac number, because 21221202423 - 2¹⁴ = 21221186039 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21221202423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221202463) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2048565 + ... + 2058897.

It is an arithmetic number, because the mean of its divisors is an integer number (924479640).

Almost surely, 2^21221202423 is an apocalyptic number.

21221202423 is a deficient number, since it is larger than the sum of its proper divisors (8362146057).

21221202423 is a wasteful number, since it uses less digits than its factorization.

21221202423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10719.

The product of its (nonzero) digits is 768, while the sum is 21.

Adding to 21221202423 its reverse (32420212212), we get a palindrome (53641414635).

The spelling of 21221202423 in words is "twenty-one billion, two hundred twenty-one million, two hundred two thousand, four hundred twenty-three".