21001212001 has 8 divisors (see below), whose sum is σ = 26183329344. Its totient is φ = 16364580720.

The previous prime is 21001211977. The next prime is 21001212007. The reversal of 21001212001 is 10021210012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21001212001 - 2⁵ = 21001211969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001212007) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 136371430 + ... + 136371583.

It is an arithmetic number, because the mean of its divisors is an integer number (3272916168).

Almost surely, 2^21001212001 is an apocalyptic number.

It is an amenable number.

21001212001 is a deficient number, since it is larger than the sum of its proper divisors (5182117343).

21001212001 is a wasteful number, since it uses less digits than its factorization.

21001212001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272743031.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21001212001 its reverse (10021210012), we get a palindrome (31022422013).

The spelling of 21001212001 in words is "twenty-one billion, one million, two hundred twelve thousand, one".