21945201328680 has 256 divisors, whose sum is σ = 77718680616960. Its totient is φ = 4851058636800.

The previous prime is 21945201328663. The next prime is 21945201328697. The reversal of 21945201328680 is 8682310254912.

It is an interprime number because it is at equal distance from previous prime (21945201328663) and next prime (21945201328697).

It is a super-2 number, since 2×21945201328680² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 39592012 + ... + 40142468.

It is an arithmetic number, because the mean of its divisors is an integer number (303588596160).

Almost surely, 2^{21945201328680} is an apocalyptic number.

21945201328680 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 21945201328680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38859340308480).

21945201328680 is an abundant number, since it is smaller than the sum of its proper divisors (55773479288280).

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

21945201328680 is a wasteful number, since it uses less digits than its factorization.

21945201328680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 552040 (or 552036 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 51.

The spelling of 21945201328680 in words is "twenty-one trillion, nine hundred forty-five billion, two hundred one million, three hundred twenty-eight thousand, six hundred eighty".