21641852670 has 64 divisors (see below), whose sum is σ = 52832618496. Its totient is φ = 5672177280.

The previous prime is 21641852647. The next prime is 21641852671. The reversal of 21641852670 is 7625814612.

It is a happy number.

It is a super-2 number, since 2×21641852670² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21641852671) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2863837 + ... + 2871383.

It is an arithmetic number, because the mean of its divisors is an integer number (825509664).

Almost surely, 2^21641852670 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21641852670, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26416309248).

21641852670 is an abundant number, since it is smaller than the sum of its proper divisors (31190765826).

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

21641852670 is a wasteful number, since it uses less digits than its factorization.

21641852670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9185.

The product of its (nonzero) digits is 161280, while the sum is 42.

The spelling of 21641852670 in words is "twenty-one billion, six hundred forty-one million, eight hundred fifty-two thousand, six hundred seventy".