6499981920 has 96 divisors (see below), whose sum is σ = 20636356608. Its totient is φ = 1719664128.

The previous prime is 6499981897. The next prime is 6499981921. The reversal of 6499981920 is 291899946.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6499981921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7647 + ... + 114273.

It is an arithmetic number, because the mean of its divisors is an integer number (214962048).

Almost surely, 2^6499981920 is an apocalyptic number.

6499981920 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 6499981920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10318178304).

6499981920 is an abundant number, since it is smaller than the sum of its proper divisors (14136374688).

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

6499981920 is a wasteful number, since it uses less digits than its factorization.

6499981920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106772 (or 106764 counting only the distinct ones).

The product of its (nonzero) digits is 2519424, while the sum is 57.

The square root of 6499981920 is about 80622.4653555075. The cubic root of 6499981920 is about 1866.2538480531.

The spelling of 6499981920 in words is "six billion, four hundred ninety-nine million, nine hundred eighty-one thousand, nine hundred twenty".