21134145747720 has 128 divisors (see below), whose sum is σ = 64364390553600. Its totient is φ = 5550306153216.

The previous prime is 21134145747719. The next prime is 21134145747727. The reversal of 21134145747720 is 2774754143112.

It is a self number, because there is not a number n which added to its sum of digits gives 21134145747720.

It is not an unprimeable number, because it can be changed into a prime (21134145747727) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 32960017 + ... + 33595103.

It is an arithmetic number, because the mean of its divisors is an integer number (502846801200).

Almost surely, 2^{21134145747720} is an apocalyptic number.

21134145747720 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 21134145747720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32182195276800).

21134145747720 is an abundant number, since it is smaller than the sum of its proper divisors (43230244805880).

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

21134145747720 is a wasteful number, since it uses less digits than its factorization.

21134145747720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639307 (or 639303 counting only the distinct ones).

The product of its (nonzero) digits is 1317120, while the sum is 48.

The spelling of 21134145747720 in words is "twenty-one trillion, one hundred thirty-four billion, one hundred forty-five million, seven hundred forty-seven thousand, seven hundred twenty".