1264381440 has 320 divisors, whose sum is σ = 4784693760. Its totient is φ = 278691840.

The previous prime is 1264381423. The next prime is 1264381441. The reversal of 1264381440 is 441834621.

It is a tau number, because it is divible by the number of its divisors (320).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1264381441) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1558635 + ... + 1559445.

It is an arithmetic number, because the mean of its divisors is an integer number (14952168).

Almost surely, 2^1264381440 is an apocalyptic number.

1264381440 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 1264381440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2392346880).

1264381440 is an abundant number, since it is smaller than the sum of its proper divisors (3520312320).

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

1264381440 is an equidigital number, since it uses as much as digits as its factorization.

1264381440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 873 (or 857 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 33.

The square root of 1264381440 is about 35558.1416837269. The cubic root of 1264381440 is about 1081.3327853128.

The spelling of 1264381440 in words is "one billion, two hundred sixty-four million, three hundred eighty-one thousand, four hundred forty".