3121181521920 has 1728 divisors, whose sum is σ = 14454401270400. Its totient is φ = 614236815360.

The previous prime is 3121181521883. The next prime is 3121181521921. The reversal of 3121181521920 is 291251811213.

3121181521920 is a `hidden beast` number, since 3 + 12 + 118 + 1 + 521 + 9 + 2 + 0 = 666.

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 (3121181521921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 943808907 + ... + 943812213.

It is an arithmetic number, because the mean of its divisors is an integer number (8364815550).

Almost surely, 2^{3121181521920} is an apocalyptic number.

3121181521920 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 3121181521920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7227200635200).

3121181521920 is an abundant number, since it is smaller than the sum of its proper divisors (11333219748480).

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

3121181521920 is a wasteful number, since it uses less digits than its factorization.

3121181521920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3384 (or 3354 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 36.

The spelling of 3121181521920 in words is "three trillion, one hundred twenty-one billion, one hundred eighty-one million, five hundred twenty-one thousand, nine hundred twenty".