2131221440 has 56 divisors (see below), whose sum is σ = 5086331712. Its totient is φ = 850580480.

The previous prime is 2131221437. The next prime is 2131221509. The reversal of 2131221440 is 441221312.

It is a Harshad number since it is a multiple of its sum of digits (20).

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, 140297 + ... + 154743.

It is an arithmetic number, because the mean of its divisors is an integer number (90827352).

Almost surely, 2^2131221440 is an apocalyptic number.

2131221440 is a gapful number since it is divisible by the number (20) 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 2131221440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2543165856).

2131221440 is an abundant number, since it is smaller than the sum of its proper divisors (2955110272).

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

2131221440 is a wasteful number, since it uses less digits than its factorization.

2131221440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14925 (or 14915 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 2131221440 is about 46165.1539583699. The cubic root of 2131221440 is about 1286.8942453482.

Adding to 2131221440 its reverse (441221312), we get a palindrome (2572442752).

The spelling of 2131221440 in words is "two billion, one hundred thirty-one million, two hundred twenty-one thousand, four hundred forty".