21602172152 has 64 divisors (see below), whose sum is σ = 45744652800. Its totient is φ = 9473376640.

The previous prime is 21602172139. The next prime is 21602172161. The reversal of 21602172152 is 25127120612.

It is a happy number.

It is a super-2 number, since 2×21602172152² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4711253 + ... + 4715835.

It is an arithmetic number, because the mean of its divisors is an integer number (714760200).

Almost surely, 2^21602172152 is an apocalyptic number.

21602172152 is a gapful number since it is divisible by the number (22) 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 21602172152, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22872326400).

21602172152 is an abundant number, since it is smaller than the sum of its proper divisors (24142480648).

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

21602172152 is a wasteful number, since it uses less digits than its factorization.

21602172152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6476 (or 6472 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 29.

Adding to 21602172152 its reverse (25127120612), we get a palindrome (46729292764).

The spelling of 21602172152 in words is "twenty-one billion, six hundred two million, one hundred seventy-two thousand, one hundred fifty-two".