21661035522360 has 256 divisors, whose sum is σ = 70151099397120. Its totient is φ = 5319057408000.

The previous prime is 21661035522359. The next prime is 21661035522383. The reversal of 21661035522360 is 6322553016612.

It is a happy number.

It is a congruent 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, 3432263605 + ... + 3432269915.

It is an arithmetic number, because the mean of its divisors is an integer number (274027732020).

Almost surely, 2^{21661035522360} is an apocalyptic number.

21661035522360 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 21661035522360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35075549698560).

21661035522360 is an abundant number, since it is smaller than the sum of its proper divisors (48490063874760).

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

21661035522360 is a wasteful number, since it uses less digits than its factorization.

21661035522360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11310 (or 11306 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 42.

Adding to 21661035522360 its reverse (6322553016612), we get a palindrome (27983588538972).

The spelling of 21661035522360 in words is "twenty-one trillion, six hundred sixty-one billion, thirty-five million, five hundred twenty-two thousand, three hundred sixty".