21125356618806 has 96 divisors (see below), whose sum is σ = 52591041434880. Its totient is φ = 6061194273600.

The previous prime is 21125356618799. The next prime is 21125356618811. The reversal of 21125356618806 is 60881665352112.

21125356618806 is a `hidden beast` number, since 2 + 1 + 12 + 5 + 3 + 5 + 6 + 618 + 8 + 0 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4899391 + ... + 8139701.

It is an arithmetic number, because the mean of its divisors is an integer number (547823348280).

Almost surely, 2^{21125356618806} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21125356618806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26295520717440).

21125356618806 is an abundant number, since it is smaller than the sum of its proper divisors (31465684816074).

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

21125356618806 is a wasteful number, since it uses less digits than its factorization.

21125356618806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3242082 (or 3242079 counting only the distinct ones).

The product of its (nonzero) digits is 4147200, while the sum is 54.

The spelling of 21125356618806 in words is "twenty-one trillion, one hundred twenty-five billion, three hundred fifty-six million, six hundred eighteen thousand, eight hundred six".