6217621920 has 144 divisors (see below), whose sum is σ = 21240765000. Its totient is φ = 1656225792.

The previous prime is 6217621889. The next prime is 6217621979. The reversal of 6217621920 is 291267126.

6217621920 is a `hidden beast` number, since 6 + 2 + 1 + 7 + 621 + 9 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2758770576 + 3458851344 = 52524^2 + 58812^2 .

It is a tau number, because it is divible by the number of its divisors (144).

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1796832 + ... + 1800288.

Almost surely, 2^6217621920 is an apocalyptic number.

6217621920 is a gapful number since it is divisible by the number (60) 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 6217621920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10620382500).

6217621920 is an abundant number, since it is smaller than the sum of its proper divisors (15023143080).

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

6217621920 is a wasteful number, since it uses less digits than its factorization.

6217621920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4727 (or 4716 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 6217621920 is about 78851.8986454987. The cubic root of 6217621920 is about 1838.8293908915.

The spelling of 6217621920 in words is "six billion, two hundred seventeen million, six hundred twenty-one thousand, nine hundred twenty".