1212505409 has 2 divisors, whose sum is σ = 1212505410. Its totient is φ = 1212505408.

The previous prime is 1212505397. The next prime is 1212505447. The reversal of 1212505409 is 9045052121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 722104384 + 490401025 = 26872^2 + 22145^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212505409 - 2²⁸ = 944069953 is a prime.

It is not a weakly prime, because it can be changed into another prime (1212535409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606252704 + 606252705.

It is an arithmetic number, because the mean of its divisors is an integer number (606252705).

Almost surely, 2^1212505409 is an apocalyptic number.

It is an amenable number.

1212505409 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212505409 is an equidigital number, since it uses as much as digits as its factorization.

1212505409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 1212505409 is about 34821.0483615873. The cubic root of 1212505409 is about 1066.3372034026.

The spelling of 1212505409 in words is "one billion, two hundred twelve million, five hundred five thousand, four hundred nine".