21253155735672 has 320 divisors, whose sum is σ = 68819773176000. Its totient is φ = 6002114494464.

The previous prime is 21253155735661. The next prime is 21253155735673. The reversal of 21253155735672 is 27653755135212.

21253155735672 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 3 + 1 + 5 + 5 + 73 + 567 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253155735673) 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 79 ways as a sum of consecutive naturals, for example, 1569998088 + ... + 1570011624.

It is an arithmetic number, because the mean of its divisors is an integer number (215061791175).

Almost surely, 2^{21253155735672} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21253155735672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34409886588000).

21253155735672 is an abundant number, since it is smaller than the sum of its proper divisors (47566617440328).

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

21253155735672 is a wasteful number, since it uses less digits than its factorization.

21253155735672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17540 (or 17527 counting only the distinct ones).

The product of its digits is 13230000, while the sum is 54.

The spelling of 21253155735672 in words is "twenty-one trillion, two hundred fifty-three billion, one hundred fifty-five million, seven hundred thirty-five thousand, six hundred seventy-two".