21001212007 has 2 divisors, whose sum is σ = 21001212008. Its totient is φ = 21001212006.

The previous prime is 21001211977. The next prime is 21001212017. The reversal of 21001212007 is 70021210012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21001212007 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001212017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500606003 + 10500606004.

It is an arithmetic number, because the mean of its divisors is an integer number (10500606004).

Almost surely, 2^21001212007 is an apocalyptic number.

21001212007 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001212007 is an equidigital number, since it uses as much as digits as its factorization.

21001212007 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56, while the sum is 16.

Adding to 21001212007 its reverse (70021210012), we get a palindrome (91022422019).

The spelling of 21001212007 in words is "twenty-one billion, one million, two hundred twelve thousand, seven".