21405150720 has 480 divisors, whose sum is σ = 80968567680. Its totient is φ = 5404631040.

The previous prime is 21405150703. The next prime is 21405150731. The reversal of 21405150720 is 2705150412.

21405150720 is a `hidden beast` number, since 2 + 140 + 515 + 0 + 7 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11818615 + ... + 11820425.

It is an arithmetic number, because the mean of its divisors is an integer number (168684516).

Almost surely, 2^21405150720 is an apocalyptic number.

21405150720 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 21405150720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40484283840).

21405150720 is an abundant number, since it is smaller than the sum of its proper divisors (59563416960).

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

21405150720 is an equidigital number, since it uses as much as digits as its factorization.

21405150720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1868 (or 1840 counting only the distinct ones).

The product of its (nonzero) digits is 2800, while the sum is 27.

The spelling of 21405150720 in words is "twenty-one billion, four hundred five million, one hundred fifty thousand, seven hundred twenty".