1266400388 has 48 divisors (see below), whose sum is σ = 2575722240. Its totient is φ = 538740000.

The previous prime is 1266400351. The next prime is 1266400393. The reversal of 1266400388 is 8830046621.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60263 + ... + 78513.

It is an arithmetic number, because the mean of its divisors is an integer number (53660880).

Almost surely, 2^1266400388 is an apocalyptic number.

It is an amenable number.

1266400388 is an abundant number, since it is smaller than the sum of its proper divisors (1309321852).

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

1266400388 is a wasteful number, since it uses less digits than its factorization.

1266400388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18368 (or 18366 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 38.

The square root of 1266400388 is about 35586.5197511642. The cubic root of 1266400388 is about 1081.9080319944.

The spelling of 1266400388 in words is "one billion, two hundred sixty-six million, four hundred thousand, three hundred eighty-eight".