21534537745770 has 256 divisors, whose sum is σ = 61154928046080. Its totient is φ = 4751046752256.

The previous prime is 21534537745681. The next prime is 21534537745783. The reversal of 21534537745770 is 7754773543512.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 395152644 + ... + 395207136.

It is an arithmetic number, because the mean of its divisors is an integer number (238886437680).

Almost surely, 2^{21534537745770} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21534537745770, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30577464023040).

21534537745770 is an abundant number, since it is smaller than the sum of its proper divisors (39620390300310).

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

21534537745770 is a wasteful number, since it uses less digits than its factorization.

21534537745770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55069.

The product of its (nonzero) digits is 86436000, while the sum is 60.

The spelling of 21534537745770 in words is "twenty-one trillion, five hundred thirty-four billion, five hundred thirty-seven million, seven hundred forty-five thousand, seven hundred seventy".