21126363720 has 384 divisors, whose sum is σ = 84667161600. Its totient is φ = 4158604800.

The previous prime is 21126363703. The next prime is 21126363763. The reversal of 21126363720 is 2736362112.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1220325 + ... + 1237515.

It is an arithmetic number, because the mean of its divisors is an integer number (220487400).

Almost surely, 2^21126363720 is an apocalyptic number.

21126363720 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 21126363720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42333580800).

21126363720 is an abundant number, since it is smaller than the sum of its proper divisors (63540797880).

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

21126363720 is a wasteful number, since it uses less digits than its factorization.

21126363720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17249 (or 17238 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 33.

The spelling of 21126363720 in words is "twenty-one billion, one hundred twenty-six million, three hundred sixty-three thousand, seven hundred twenty".