21552212240 has 160 divisors (see below), whose sum is σ = 57371328000. Its totient is φ = 7463577600.

The previous prime is 21552212239. The next prime is 21552212273. The reversal of 21552212240 is 4221225512.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1990361 + ... + 2001159.

It is an arithmetic number, because the mean of its divisors is an integer number (358570800).

Almost surely, 2^21552212240 is an apocalyptic number.

21552212240 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 21552212240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28685664000).

21552212240 is an abundant number, since it is smaller than the sum of its proper divisors (35819115760).

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

21552212240 is a wasteful number, since it uses less digits than its factorization.

21552212240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10945 (or 10939 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 26.

Adding to 21552212240 its reverse (4221225512), we get a palindrome (25773437752).

The spelling of 21552212240 in words is "twenty-one billion, five hundred fifty-two million, two hundred twelve thousand, two hundred forty".