21121002207 has 8 divisors (see below), whose sum is σ = 31290373680. Its totient is φ = 14080668120.

The previous prime is 21121002187. The next prime is 21121002211. The reversal of 21121002207 is 70220012112.

It is a happy number.

It is not a de Polignac number, because 21121002207 - 2¹⁰ = 21121001183 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21121002207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121002247) 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, 391129644 + ... + 391129697.

It is an arithmetic number, because the mean of its divisors is an integer number (3911296710).

Almost surely, 2^21121002207 is an apocalyptic number.

21121002207 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21121002207 is a deficient number, since it is larger than the sum of its proper divisors (10169371473).

21121002207 is an equidigital number, since it uses as much as digits as its factorization.

21121002207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 782259350 (or 782259344 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

Adding to 21121002207 its reverse (70220012112), we get a palindrome (91341014319).

The spelling of 21121002207 in words is "twenty-one billion, one hundred twenty-one million, two thousand, two hundred seven".