26121861556640 has 384 divisors, whose sum is σ = 64524424656384. Its totient is φ = 9986457600000.

The previous prime is 26121861556601. The next prime is 26121861556643. The reversal of 26121861556640 is 4665516812162.

It is not an unprimeable number, because it can be changed into a prime (26121861556643) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 25287377564 + ... + 25287378596.

It is an arithmetic number, because the mean of its divisors is an integer number (168032355876).

Almost surely, 2^{26121861556640} is an apocalyptic number.

26121861556640 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 26121861556640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32262212328192).

26121861556640 is an abundant number, since it is smaller than the sum of its proper divisors (38402563099744).

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

26121861556640 is a wasteful number, since it uses less digits than its factorization.

26121861556640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1584 (or 1576 counting only the distinct ones).

The product of its (nonzero) digits is 4147200, while the sum is 53.

The spelling of 26121861556640 in words is "twenty-six trillion, one hundred twenty-one billion, eight hundred sixty-one million, five hundred fifty-six thousand, six hundred forty".