20721173760 has 864 divisors, whose sum is σ = 87996260352. Its totient is φ = 4568555520.

The previous prime is 20721173743. The next prime is 20721173761. The reversal of 20721173760 is 6737112702.

It is a tau number, because it is divible by the number of its divisors (864).

It is a super-2 number, since 2×20721173760² (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 congruent number.

It is not an unprimeable number, because it can be changed into a prime (20721173761) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 67495527 + ... + 67495833.

Almost surely, 2^20721173760 is an apocalyptic number.

20721173760 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 20721173760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43998130176).

20721173760 is an abundant number, since it is smaller than the sum of its proper divisors (67275086592).

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

20721173760 is an equidigital number, since it uses as much as digits as its factorization.

20721173760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381 (or 355 counting only the distinct ones).

The product of its (nonzero) digits is 24696, while the sum is 36.

It can be divided in two parts, 20721 and 173760, that added together give a 4-th power (194481 = 21⁴).

The spelling of 20721173760 in words is "twenty billion, seven hundred twenty-one million, one hundred seventy-three thousand, seven hundred sixty".