21021220007 has 2 divisors, whose sum is σ = 21021220008. Its totient is φ = 21021220006.

The previous prime is 21021219883. The next prime is 21021220039. The reversal of 21021220007 is 70002212012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21021220007 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021225007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510610003 + 10510610004.

It is an arithmetic number, because the mean of its divisors is an integer number (10510610004).

Almost surely, 2^21021220007 is an apocalyptic number.

21021220007 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021220007 is an equidigital number, since it uses as much as digits as its factorization.

21021220007 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 112, while the sum is 17.

Adding to 21021220007 its reverse (70002212012), we get a palindrome (91023432019).

The spelling of 21021220007 in words is "twenty-one billion, twenty-one million, two hundred twenty thousand, seven".