21021240001 has 2 divisors, whose sum is σ = 21021240002. Its totient is φ = 21021240000.

The previous prime is 21021239999. The next prime is 21021240029. The reversal of 21021240001 is 10004212012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20177918401 + 843321600 = 142049^2 + 29040^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021240001 - 2¹ = 21021239999 is a prime.

Together with 21021239999, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21021240041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510620000 + 10510620001.

It is an arithmetic number, because the mean of its divisors is an integer number (10510620001).

Almost surely, 2^21021240001 is an apocalyptic number.

It is an amenable number.

21021240001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021240001 is an equidigital number, since it uses as much as digits as its factorization.

21021240001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21021240001 its reverse (10004212012), we get a palindrome (31025452013).

The spelling of 21021240001 in words is "twenty-one billion, twenty-one million, two hundred forty thousand, one".