64879920 has 240 divisors, whose sum is σ = 260385120. Its totient is φ = 14805504.

The previous prime is 64879909. The next prime is 64879921. The reversal of 64879920 is 2997846.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (64879921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 105534 + ... + 106146.

It is an arithmetic number, because the mean of its divisors is an integer number (1084938).

Almost surely, 2^64879920 is an apocalyptic number.

64879920 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 64879920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130192560).

64879920 is an abundant number, since it is smaller than the sum of its proper divisors (195505200).

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

64879920 is a wasteful number, since it uses less digits than its factorization.

64879920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 649 (or 630 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The square root of 64879920 is about 8054.8072602639. The cubic root of 64879920 is about 401.8248290047.

The spelling of 64879920 in words is "sixty-four million, eight hundred seventy-nine thousand, nine hundred twenty".