1321297920 has 384 divisors, whose sum is σ = 4835376000. Its totient is φ = 346374144.

The previous prime is 1321297907. The next prime is 1321297921. The reversal of 1321297920 is 297921231.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321297921) 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, 22394851 + ... + 22394909.

It is an arithmetic number, because the mean of its divisors is an integer number (12592125).

Almost surely, 2^1321297920 is an apocalyptic number.

1321297920 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 1321297920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2417688000).

1321297920 is an abundant number, since it is smaller than the sum of its proper divisors (3514078080).

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

1321297920 is an frugal number, since it uses more digits than its factorization.

1321297920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107 (or 69 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 1321297920 is about 36349.6618966394. The cubic root of 1321297920 is about 1097.3207300896.

The spelling of 1321297920 in words is "one billion, three hundred twenty-one million, two hundred ninety-seven thousand, nine hundred twenty".