1243691928 has 64 divisors (see below), whose sum is σ = 3457612800. Its totient is φ = 414214560.

The previous prime is 1243691927. The next prime is 1243691951. The reversal of 1243691928 is 8291963421.

It is a super-2 number, since 2×1243691928² = 3093539223544714368, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1243691927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 444213 + ... + 447003.

It is an arithmetic number, because the mean of its divisors is an integer number (54025200).

Almost surely, 2^1243691928 is an apocalyptic number.

1243691928 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1243691928 is an abundant number, since it is smaller than the sum of its proper divisors (2213920872).

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

1243691928 is a wasteful number, since it uses less digits than its factorization.

1243691928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4869 (or 4859 counting only the distinct ones).

The product of its digits is 186624, while the sum is 45.

The square root of 1243691928 is about 35266.0166165673. The cubic root of 1243691928 is about 1075.4022444213.

The spelling of 1243691928 in words is "one billion, two hundred forty-three million, six hundred ninety-one thousand, nine hundred twenty-eight".