1211656631 has 2 divisors, whose sum is σ = 1211656632. Its totient is φ = 1211656630.

The previous prime is 1211656571. The next prime is 1211656639. The reversal of 1211656631 is 1366561121.

It is a strong prime.

It is an emirp because it is prime and its reverse (1366561121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1211656631 - 2¹⁰ = 1211655607 is a prime.

It is a super-2 number, since 2×1211656631² = 2936223582892540322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211656639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605828315 + 605828316.

It is an arithmetic number, because the mean of its divisors is an integer number (605828316).

Almost surely, 2^1211656631 is an apocalyptic number.

1211656631 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211656631 is an equidigital number, since it uses as much as digits as its factorization.

1211656631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 32.

The square root of 1211656631 is about 34808.8585133153. The cubic root of 1211656631 is about 1066.0883262082.

The spelling of 1211656631 in words is "one billion, two hundred eleven million, six hundred fifty-six thousand, six hundred thirty-one".