1231687156 has 12 divisors (see below), whose sum is σ = 2463374368. Its totient is φ = 527865912.

The previous prime is 1231687153. The next prime is 1231687157. The reversal of 1231687156 is 6517861321.

It is a happy number.

1231687156 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231687151) 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, 21994386 + ... + 21994441.

Almost surely, 2^1231687156 is an apocalyptic number.

It is an amenable number.

1231687156 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1231687156 is a wasteful number, since it uses less digits than its factorization.

1231687156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43988838 (or 43988836 counting only the distinct ones).

The product of its digits is 60480, while the sum is 40.

The square root of 1231687156 is about 35095.4007812990. The cubic root of 1231687156 is about 1071.9309343731.

The spelling of 1231687156 in words is "one billion, two hundred thirty-one million, six hundred eighty-seven thousand, one hundred fifty-six".