1331378784 has 144 divisors (see below), whose sum is σ = 3868300800. Its totient is φ = 434274048.

The previous prime is 1331378767. The next prime is 1331378791. The reversal of 1331378784 is 4878731331.

1331378784 = T₃₉₆₀ + T₃₉₆₁ + ... + T₄₁₂₂.

1331378784 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-3 number, since 3×1331378784³ (a number of 28 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3708397 + ... + 3708755.

It is an arithmetic number, because the mean of its divisors is an integer number (26863200).

Almost surely, 2^1331378784 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1331378784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1934150400).

1331378784 is an abundant number, since it is smaller than the sum of its proper divisors (2536922016).

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

1331378784 is a wasteful number, since it uses less digits than its factorization.

1331378784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 617 (or 606 counting only the distinct ones).

The product of its digits is 338688, while the sum is 45.

The square root of 1331378784 is about 36488.0635824923. The cubic root of 1331378784 is about 1100.1043383123.

The spelling of 1331378784 in words is "one billion, three hundred thirty-one million, three hundred seventy-eight thousand, seven hundred eighty-four".