321261523440 has 240 divisors, whose sum is σ = 1176451309440. Its totient is φ = 71890590720.

The previous prime is 321261523439. The next prime is 321261523459. The reversal of 321261523440 is 44325162123.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 86131 + ... + 806189.

It is an arithmetic number, because the mean of its divisors is an integer number (4901880456).

Almost surely, 2^321261523440 is an apocalyptic number.

321261523440 is a gapful number since it is divisible by the number (30) 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 321261523440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (588225654720).

321261523440 is an abundant number, since it is smaller than the sum of its proper divisors (855189786000).

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

321261523440 is a wasteful number, since it uses less digits than its factorization.

321261523440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 720112 (or 720093 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 33.

Adding to 321261523440 its reverse (44325162123), we get a palindrome (365586685563).

The spelling of 321261523440 in words is "three hundred twenty-one billion, two hundred sixty-one million, five hundred twenty-three thousand, four hundred forty".