20965712640 has 288 divisors, whose sum is σ = 71135124480. Its totient is φ = 5247664128.

The previous prime is 20965712549. The next prime is 20965712657. The reversal of 20965712640 is 4621756902.

It is a super-2 number, since 2×20965712640² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20965712592 and 20965712601.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8243209 + ... + 8245751.

It is an arithmetic number, because the mean of its divisors is an integer number (246996960).

Almost surely, 2^20965712640 is an apocalyptic number.

20965712640 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 20965712640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35567562240).

20965712640 is an abundant number, since it is smaller than the sum of its proper divisors (50169411840).

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

20965712640 is a wasteful number, since it uses less digits than its factorization.

20965712640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2699 (or 2685 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 42.

The spelling of 20965712640 in words is "twenty billion, nine hundred sixty-five million, seven hundred twelve thousand, six hundred forty".