21434615720 has 128 divisors (see below), whose sum is σ = 57240691200. Its totient is φ = 7067913216.

The previous prime is 21434615717. The next prime is 21434615753. The reversal of 21434615720 is 2751643412.

It is a super-2 number, since 2×21434615720² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2130542 + ... + 2140578.

It is an arithmetic number, because the mean of its divisors is an integer number (447192900).

Almost surely, 2^21434615720 is an apocalyptic number.

21434615720 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 21434615720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28620345600).

21434615720 is an abundant number, since it is smaller than the sum of its proper divisors (35806075480).

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

21434615720 is a wasteful number, since it uses less digits than its factorization.

21434615720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10347 (or 10343 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 35.

The spelling of 21434615720 in words is "twenty-one billion, four hundred thirty-four million, six hundred fifteen thousand, seven hundred twenty".