1311666278400 has 351 divisors, whose sum is σ = 4702047883039. Its totient is φ = 349484482560.

The previous prime is 1311666278389. The next prime is 1311666278413. The reversal of 1311666278400 is 48726661131.

The square root of 1311666278400 is 1145280.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 21461078016 + 1290205200384 = 146496^2 + 1135872^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1099468204 + ... + 1099469396.

Almost surely, 2^{1311666278400} is an apocalyptic number.

1311666278400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1311666278400 is the 1145280-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1311666278400

1311666278400 is an abundant number, since it is smaller than the sum of its proper divisors (3390381604639).

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

1311666278400 is an frugal number, since it uses more digits than its factorization.

1311666278400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2426 (or 1203 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The spelling of 1311666278400 in words is "one trillion, three hundred eleven billion, six hundred sixty-six million, two hundred seventy-eight thousand, four hundred".