21131850240 has 400 divisors, whose sum is σ = 76512747960. Its totient is φ = 5573836800.

The previous prime is 21131850209. The next prime is 21131850283. The reversal of 21131850240 is 4205813112.

21131850240 is a `hidden beast` number, since 2 + 113 + 1 + 8 + 502 + 40 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 19631372544 + 1500477696 = 140112^2 + 38736^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 20942856 + ... + 20943864.

Almost surely, 2^21131850240 is an apocalyptic number.

21131850240 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 21131850240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38256373980).

21131850240 is an abundant number, since it is smaller than the sum of its proper divisors (55380897720).

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

21131850240 is a wasteful number, since it uses less digits than its factorization.

21131850240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1145 (or 1120 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The spelling of 21131850240 in words is "twenty-one billion, one hundred thirty-one million, eight hundred fifty thousand, two hundred forty".