21121661326524 has 96 divisors (see below), whose sum is σ = 53794895078400. Its totient is φ = 6396854031360.

The previous prime is 21121661326523. The next prime is 21121661326531. The reversal of 21121661326524 is 42562316612112.

It is a super-2 number, since 2×21121661326524² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121661326523) 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, 2942961624 + ... + 2942968800.

It is an arithmetic number, because the mean of its divisors is an integer number (560363490400).

Almost surely, 2^{21121661326524} is an apocalyptic number.

It is an amenable number.

21121661326524 is an abundant number, since it is smaller than the sum of its proper divisors (32673233751876).

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

21121661326524 is a wasteful number, since it uses less digits than its factorization.

21121661326524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16803 (or 16801 counting only the distinct ones).

The product of its digits is 207360, while the sum is 42.

Adding to 21121661326524 its reverse (42562316612112), we get a palindrome (63683977938636).

The spelling of 21121661326524 in words is "twenty-one trillion, one hundred twenty-one billion, six hundred sixty-one million, three hundred twenty-six thousand, five hundred twenty-four".