21031304040 has 96 divisors (see below), whose sum is σ = 68420008800. Its totient is φ = 5602746240.

The previous prime is 21031304039. The next prime is 21031304057. The reversal of 21031304040 is 4040313012.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 338175 + ... + 395505.

It is an arithmetic number, because the mean of its divisors is an integer number (712708425).

Almost surely, 2^21031304040 is an apocalyptic number.

21031304040 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 21031304040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34210004400).

21031304040 is an abundant number, since it is smaller than the sum of its proper divisors (47388704760).

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

21031304040 is a wasteful number, since it uses less digits than its factorization.

21031304040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58367 (or 58360 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

Adding to 21031304040 its reverse (4040313012), we get a palindrome (25071617052).

The spelling of 21031304040 in words is "twenty-one billion, thirty-one million, three hundred four thousand, forty".