21126550536 has 192 divisors, whose sum is σ = 70539880320. Its totient is φ = 5562501120.

The previous prime is 21126550531. The next prime is 21126550537. The reversal of 21126550536 is 63505562112.

21126550536 is a `hidden beast` number, since 2 + 1 + 12 + 65 + 50 + 536 = 666.

It is a super-2 number, since 2×21126550536² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21126550536.

It is not an unprimeable number, because it can be changed into a prime (21126550531) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4472656 + ... + 4477376.

It is an arithmetic number, because the mean of its divisors is an integer number (367395210).

Almost surely, 2^21126550536 is an apocalyptic number.

21126550536 is a gapful number since it is divisible by the number (26) 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 21126550536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35269940160).

21126550536 is an abundant number, since it is smaller than the sum of its proper divisors (49413329784).

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

21126550536 is a wasteful number, since it uses less digits than its factorization.

21126550536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5436 (or 5429 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 36.

The spelling of 21126550536 in words is "twenty-one billion, one hundred twenty-six million, five hundred fifty thousand, five hundred thirty-six".