21447112170 has 128 divisors (see below), whose sum is σ = 57072936960. Its totient is φ = 5114753280.

The previous prime is 21447112157. The next prime is 21447112187. The reversal of 21447112170 is 7121174412.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5334421 + ... + 5338439.

It is an arithmetic number, because the mean of its divisors is an integer number (445882320).

Almost surely, 2^21447112170 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21447112170, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28536468480).

21447112170 is an abundant number, since it is smaller than the sum of its proper divisors (35625824790).

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

21447112170 is a wasteful number, since it uses less digits than its factorization.

21447112170 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4300.

The product of its (nonzero) digits is 3136, while the sum is 30.

Adding to 21447112170 its reverse (7121174412), we get a palindrome (28568286582).

The spelling of 21447112170 in words is "twenty-one billion, four hundred forty-seven million, one hundred twelve thousand, one hundred seventy".