21004413243240 has 192 divisors, whose sum is σ = 73316082173760. Its totient is φ = 4800028477440.

The previous prime is 21004413243197. The next prime is 21004413243263. The reversal of 21004413243240 is 4234231440012.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21004413243198 and 21004413243207.

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, 28632064 + ... + 29356496.

It is an arithmetic number, because the mean of its divisors is an integer number (381854594655).

Almost surely, 2^{21004413243240} is an apocalyptic number.

21004413243240 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 21004413243240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36658041086880).

21004413243240 is an abundant number, since it is smaller than the sum of its proper divisors (52311668930520).

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

21004413243240 is a wasteful number, since it uses less digits than its factorization.

21004413243240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 729392 (or 729381 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 30.

Adding to 21004413243240 its reverse (4234231440012), we get a palindrome (25238644683252).

The spelling of 21004413243240 in words is "twenty-one trillion, four billion, four hundred thirteen million, two hundred forty-three thousand, two hundred forty".