1231985664 has 396 divisors, whose sum is σ = 4441269456. Its totient is φ = 322043904.

The previous prime is 1231985609. The next prime is 1231985687. The reversal of 1231985664 is 4665891321.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 10902472 + ... + 10902584.

Almost surely, 2^1231985664 is an apocalyptic number.

1231985664 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1231985664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2220634728).

1231985664 is an abundant number, since it is smaller than the sum of its proper divisors (3209283792).

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

1231985664 is a wasteful number, since it uses less digits than its factorization.

1231985664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172 (or 138 counting only the distinct ones).

The product of its digits is 311040, while the sum is 45.

The square root of 1231985664 is about 35099.6533316214. The cubic root of 1231985664 is about 1072.0175240322.

The spelling of 1231985664 in words is "one billion, two hundred thirty-one million, nine hundred eighty-five thousand, six hundred sixty-four".