21620065680 has 120 divisors (see below), whose sum is σ = 72772360128. Its totient is φ = 5752251648.

The previous prime is 21620065661. The next prime is 21620065681. The reversal of 21620065680 is 8656002612.

21620065680 is a `hidden beast` number, since 21 + 620 + 0 + 6 + 5 + 6 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

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 (21620065681) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 285069 + ... + 352851.

Almost surely, 2^21620065680 is an apocalyptic number.

21620065680 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 21620065680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36386180064).

21620065680 is an abundant number, since it is smaller than the sum of its proper divisors (51152294448).

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

21620065680 is a wasteful number, since it uses less digits than its factorization.

21620065680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68245 (or 68236 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 21620065680 in words is "twenty-one billion, six hundred twenty million, sixty-five thousand, six hundred eighty".