1212645389 has 4 divisors (see below), whose sum is σ = 1212945756. Its totient is φ = 1212345024.

The previous prime is 1212645373. The next prime is 1212645407. The reversal of 1212645389 is 9835462121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 554979364 + 657666025 = 23558^2 + 25645^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212645389 - 2⁴ = 1212645373 is a prime.

It is a super-2 number, since 2×1212645389² = 2941017678925922642, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212645319) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144044 + ... + 152229.

It is an arithmetic number, because the mean of its divisors is an integer number (303236439).

Almost surely, 2^1212645389 is an apocalyptic number.

It is an amenable number.

1212645389 is a deficient number, since it is larger than the sum of its proper divisors (300367).

1212645389 is an equidigital number, since it uses as much as digits as its factorization.

1212645389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300366.

The product of its digits is 103680, while the sum is 41.

The square root of 1212645389 is about 34823.0582947564. The cubic root of 1212645389 is about 1066.3782369345.

The spelling of 1212645389 in words is "one billion, two hundred twelve million, six hundred forty-five thousand, three hundred eighty-nine".