21601542161500 has 96 divisors (see below), whose sum is σ = 53934237512064. Its totient is φ = 7403936947200.

The previous prime is 21601542161489. The next prime is 21601542161503. The reversal of 21601542161500 is 516124510612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21601542161503) 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, 10300242 + ... + 12218758.

It is an arithmetic number, because the mean of its divisors is an integer number (561814974084).

Almost surely, 2^{21601542161500} is an apocalyptic number.

21601542161500 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 21601542161500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26967118756032).

21601542161500 is an abundant number, since it is smaller than the sum of its proper divisors (32332695350564).

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

21601542161500 is a wasteful number, since it uses less digits than its factorization.

21601542161500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1921760 (or 1921748 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 34.

The spelling of 21601542161500 in words is "twenty-one trillion, six hundred one billion, five hundred forty-two million, one hundred sixty-one thousand, five hundred".