1321399280 has 40 divisors (see below), whose sum is σ = 3114352752. Its totient is φ = 521316864.

The previous prime is 1321399279. The next prime is 1321399319. The reversal of 1321399280 is 829931231.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 107294 + ... + 118973.

Almost surely, 2^1321399280 is an apocalyptic number.

1321399280 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1321399280 is an abundant number, since it is smaller than the sum of its proper divisors (1792953472).

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

1321399280 is a wasteful number, since it uses less digits than its factorization.

1321399280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226353 (or 226347 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 1321399280 is about 36351.0561057034. The cubic root of 1321399280 is about 1097.3487887591.

The spelling of 1321399280 in words is "one billion, three hundred twenty-one million, three hundred ninety-nine thousand, two hundred eighty".