12210000021 has 10 divisors (see below), whose sum is σ = 18239629782. Its totient is φ = 8139999960.

The previous prime is 12210000013. The next prime is 12210000029. The reversal of 12210000021 is 12000001221.

It is an interprime number because it is at equal distance from previous prime (12210000013) and next prime (12210000029).

It can be written as a sum of positive squares in only one way, i.e., 10798119396 + 1411880625 = 103914^2 + 37575^2 .

It is not a de Polignac number, because 12210000021 - 2³ = 12210000013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 12209999958 and 12210000012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12210000029) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 75370290 + ... + 75370451.

Almost surely, 2^12210000021 is an apocalyptic number.

It is an amenable number.

12210000021 is a deficient number, since it is larger than the sum of its proper divisors (6029629761).

12210000021 is an equidigital number, since it uses as much as digits as its factorization.

12210000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150740753 (or 150740744 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 12210000021 its reverse (12000001221), we get a palindrome (24210001242).

It can be divided in two parts, 12 and 210000021, that multiplied together give a palindrome (2520000252).

The spelling of 12210000021 in words is "twelve billion, two hundred ten million, twenty-one", and thus it is an aban number.