21243215001 has 16 divisors (see below), whose sum is σ = 28666137600. Its totient is φ = 13991480448.

The previous prime is 21243214997. The next prime is 21243215027. The reversal of 21243215001 is 10051234212.

It is not a de Polignac number, because 21243215001 - 2² = 21243214997 is a prime.

It is a super-2 number, since 2×21243215001² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21243215801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 298120 + ... + 362438.

It is an arithmetic number, because the mean of its divisors is an integer number (1791633600).

Almost surely, 2^21243215001 is an apocalyptic number.

It is an amenable number.

21243215001 is a deficient number, since it is larger than the sum of its proper divisors (7422922599).

21243215001 is a wasteful number, since it uses less digits than its factorization.

21243215001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65648.

The product of its (nonzero) digits is 480, while the sum is 21.

Adding to 21243215001 its reverse (10051234212), we get a palindrome (31294449213).

The spelling of 21243215001 in words is "twenty-one billion, two hundred forty-three million, two hundred fifteen thousand, one".