21615250440 has 576 divisors, whose sum is σ = 84435696000. Its totient is φ = 4397912064.

The previous prime is 21615250429. The next prime is 21615250469. The reversal of 21615250440 is 4405251612.

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 = 21615250398 and 21615250407.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 36085261 + ... + 36085859.

It is an arithmetic number, because the mean of its divisors is an integer number (146589750).

Almost surely, 2^21615250440 is an apocalyptic number.

21615250440 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 21615250440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42217848000).

21615250440 is an abundant number, since it is smaller than the sum of its proper divisors (62820445560).

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

21615250440 is a wasteful number, since it uses less digits than its factorization.

21615250440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 682 (or 652 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

The spelling of 21615250440 in words is "twenty-one billion, six hundred fifteen million, two hundred fifty thousand, four hundred forty".