21275715552 has 144 divisors (see below), whose sum is σ = 69114971520. Its totient is φ = 5611147776.

The previous prime is 21275715547. The next prime is 21275715563. The reversal of 21275715552 is 25551757212.

It is a super-2 number, since 2×21275715552² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19899 + ... + 207237.

It is an arithmetic number, because the mean of its divisors is an integer number (479965080).

Almost surely, 2^21275715552 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21275715552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34557485760).

21275715552 is an abundant number, since it is smaller than the sum of its proper divisors (47839255968).

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

21275715552 is a wasteful number, since it uses less digits than its factorization.

21275715552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187385 (or 187364 counting only the distinct ones).

The product of its digits is 245000, while the sum is 42.

The spelling of 21275715552 in words is "twenty-one billion, two hundred seventy-five million, seven hundred fifteen thousand, five hundred fifty-two".