21420223001 has 4 divisors (see below), whose sum is σ = 21438801972. Its totient is φ = 21401644032.

The previous prime is 21420222997. The next prime is 21420223009. The reversal of 21420223001 is 10032202412.

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 13837993225 + 7582229776 = 117635^2 + 87076^2 .

It is a cyclic number.

It is not a de Polignac number, because 21420223001 - 2² = 21420222997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21420223009) 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, 9287756 + ... + 9290061.

It is an arithmetic number, because the mean of its divisors is an integer number (5359700493).

Almost surely, 2^21420223001 is an apocalyptic number.

It is an amenable number.

21420223001 is a deficient number, since it is larger than the sum of its proper divisors (18578971).

21420223001 is a wasteful number, since it uses less digits than its factorization.

21420223001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18578970.

The product of its (nonzero) digits is 192, while the sum is 17.

Adding to 21420223001 its reverse (10032202412), we get a palindrome (31452425413).

The spelling of 21420223001 in words is "twenty-one billion, four hundred twenty million, two hundred twenty-three thousand, one".