21215440001 has 4 divisors (see below), whose sum is σ = 24246217152. Its totient is φ = 18184662852.

The previous prime is 21215439997. The next prime is 21215440007. The reversal of 21215440001 is 10004451212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21215440001 - 2² = 21215439997 is a prime.

It is a super-3 number, since 3×21215440001³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21215440007) 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, 1515388565 + ... + 1515388578.

It is an arithmetic number, because the mean of its divisors is an integer number (6061554288).

Almost surely, 2^21215440001 is an apocalyptic number.

It is an amenable number.

21215440001 is a deficient number, since it is larger than the sum of its proper divisors (3030777151).

21215440001 is an equidigital number, since it uses as much as digits as its factorization.

21215440001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3030777150.

The product of its (nonzero) digits is 320, while the sum is 20.

Adding to 21215440001 its reverse (10004451212), we get a palindrome (31219891213).

The spelling of 21215440001 in words is "twenty-one billion, two hundred fifteen million, four hundred forty thousand, one".