21651701760 has 600 divisors, whose sum is σ = 83927034576. Its totient is φ = 5308416000.

The previous prime is 21651701741. The next prime is 21651701761. The reversal of 21651701760 is 6710715612.

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

It is not an unprimeable number, because it can be changed into a prime (21651701761) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 86261635 + ... + 86261885.

Almost surely, 2^21651701760 is an apocalyptic number.

21651701760 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 21651701760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41963517288).

21651701760 is an abundant number, since it is smaller than the sum of its proper divisors (62275332816).

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

21651701760 is an equidigital number, since it uses as much as digits as its factorization.

21651701760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309 (or 274 counting only the distinct ones).

The product of its (nonzero) digits is 17640, while the sum is 36.

The spelling of 21651701760 in words is "twenty-one billion, six hundred fifty-one million, seven hundred one thousand, seven hundred sixty".