21155225040 has 120 divisors (see below), whose sum is σ = 71365432320. Its totient is φ = 5616052992.

The previous prime is 21155225027. The next prime is 21155225041. The reversal of 21155225040 is 4052255112.

21155225040 is a `hidden beast` number, since 2 + 1 + 155 + 2 + 2 + 504 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is a junction number, because it is equal to n+sod(n) for n = 21155224995 and 21155225013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155225041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 94681 + ... + 226439.

It is an arithmetic number, because the mean of its divisors is an integer number (594711936).

Almost surely, 2^21155225040 is an apocalyptic number.

21155225040 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 21155225040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35682716160).

21155225040 is an abundant number, since it is smaller than the sum of its proper divisors (50210207280).

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

21155225040 is a wasteful number, since it uses less digits than its factorization.

21155225040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132001 (or 131992 counting only the distinct ones).

The product of its (nonzero) digits is 4000, while the sum is 27.

The spelling of 21155225040 in words is "twenty-one billion, one hundred fifty-five million, two hundred twenty-five thousand, forty".