1268919640 has 64 divisors (see below), whose sum is σ = 2916466560. Its totient is φ = 496704000.

The previous prime is 1268919623. The next prime is 1268919647. The reversal of 1268919640 is 469198621.

It is a happy number.

It is a super-2 number, since 2×1268919640² = 3220314105555459200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1268919647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1591722 + ... + 1592518.

It is an arithmetic number, because the mean of its divisors is an integer number (45569790).

Almost surely, 2^1268919640 is an apocalyptic number.

1268919640 is a gapful number since it is divisible by the number (10) 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 1268919640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1458233280).

1268919640 is an abundant number, since it is smaller than the sum of its proper divisors (1647546920).

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

1268919640 is a wasteful number, since it uses less digits than its factorization.

1268919640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1612 (or 1608 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 46.

The square root of 1268919640 is about 35621.8983211170. The cubic root of 1268919640 is about 1082.6249705045.

The spelling of 1268919640 in words is "one billion, two hundred sixty-eight million, nine hundred nineteen thousand, six hundred forty".