1212531391 has 2 divisors, whose sum is σ = 1212531392. Its totient is φ = 1212531390.

The previous prime is 1212531377. The next prime is 1212531433. The reversal of 1212531391 is 1931352121.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1212531391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1212531311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606265695 + 606265696.

It is an arithmetic number, because the mean of its divisors is an integer number (606265696).

Almost surely, 2^1212531391 is an apocalyptic number.

1212531391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212531391 is an equidigital number, since it uses as much as digits as its factorization.

1212531391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1620, while the sum is 28.

The square root of 1212531391 is about 34821.4214385341. The cubic root of 1212531391 is about 1066.3448199667.

The spelling of 1212531391 in words is "one billion, two hundred twelve million, five hundred thirty-one thousand, three hundred ninety-one".