1321012320 has 48 divisors (see below), whose sum is σ = 4161190320. Its totient is φ = 352269824.

The previous prime is 1321012283. The next prime is 1321012349. The reversal of 1321012320 is 232101231.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1321012320.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1375575 + ... + 1376534.

It is an arithmetic number, because the mean of its divisors is an integer number (86691465).

Almost surely, 2^1321012320 is an apocalyptic number.

1321012320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1321012320 is an abundant number, since it is smaller than the sum of its proper divisors (2840178000).

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

1321012320 is a wasteful number, since it uses less digits than its factorization.

1321012320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2752127 (or 2752119 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 1321012320 is about 36345.7331746107. The cubic root of 1321012320 is about 1097.2416620311.

Adding to 1321012320 its reverse (232101231), we get a palindrome (1553113551).

It can be divided in two parts, 132101 and 2320, that added together give a triangular number (134421 = T₅₁₈).

The spelling of 1321012320 in words is "one billion, three hundred twenty-one million, twelve thousand, three hundred twenty".