21354419520 has 378 divisors, whose sum is σ = 85662402462. Its totient is φ = 4868462592.

The previous prime is 21354419519. The next prime is 21354419521. The reversal of 21354419520 is 2591445312.

21354419520 is a `hidden beast` number, since 2 + 1 + 3 + 544 + 1 + 95 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (21354419519) and next prime (21354419521).

It can be written as a sum of positive squares in 3 ways, for example, as 40755456 + 21313664064 = 6384^2 + 145992^2 .

It is a super-2 number, since 2×21354419520² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21354419521) by changing a digit.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 54895486 + ... + 54895874.

Almost surely, 2^21354419520 is an apocalyptic number.

21354419520 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 21354419520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42831201231).

21354419520 is an abundant number, since it is smaller than the sum of its proper divisors (64307982942).

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

21354419520 is an equidigital number, since it uses as much as digits as its factorization.

21354419520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 815 (or 406 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 21354419520 in words is "twenty-one billion, three hundred fifty-four million, four hundred nineteen thousand, five hundred twenty".