21155596224 has 224 divisors, whose sum is σ = 65781789696. Its totient is φ = 5875752960.

The previous prime is 21155596211. The next prime is 21155596247. The reversal of 21155596224 is 42269555112.

It is a tau number, because it is divible by the number of its divisors (224).

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 31 ways as a sum of consecutive naturals, for example, 6964434 + ... + 6967470.

It is an arithmetic number, because the mean of its divisors is an integer number (293668704).

Almost surely, 2^21155596224 is an apocalyptic number.

21155596224 is a gapful number since it is divisible by the number (24) 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 21155596224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32890894848).

21155596224 is an abundant number, since it is smaller than the sum of its proper divisors (44626193472).

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

21155596224 is a wasteful number, since it uses less digits than its factorization.

21155596224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3203 (or 3193 counting only the distinct ones).

The product of its digits is 216000, while the sum is 42.

The spelling of 21155596224 in words is "twenty-one billion, one hundred fifty-five million, five hundred ninety-six thousand, two hundred twenty-four".