21312122002009 has 2 divisors, whose sum is σ = 21312122002010. Its totient is φ = 21312122002008.

The previous prime is 21312122001997. The next prime is 21312122002049. The reversal of 21312122002009 is 90020022121312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21179757009609 + 132364992400 = 4602147^2 + 363820^2 .

It is a cyclic number.

It is not a de Polignac number, because 21312122002009 - 2⁹ = 21312122001497 is a prime.

It is a super-2 number, since 2×21312122002009² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21312122002049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656061001004 + 10656061001005.

It is an arithmetic number, because the mean of its divisors is an integer number (10656061001005).

Almost surely, 2^{21312122002009} is an apocalyptic number.

It is an amenable number.

21312122002009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21312122002009 is an equidigital number, since it uses as much as digits as its factorization.

21312122002009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 25.

The spelling of 21312122002009 in words is "twenty-one trillion, three hundred twelve billion, one hundred twenty-two million, two thousand, nine".