64421040 has 80 divisors (see below), whose sum is σ = 202495968. Its totient is φ = 16939008.

The previous prime is 64421017. The next prime is 64421081. The reversal of 64421040 is 4012446.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 64420998 and 64421016.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15682 + ... + 19358.

Almost surely, 2^64421040 is an apocalyptic number.

64421040 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 64421040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101247984).

64421040 is an abundant number, since it is smaller than the sum of its proper divisors (138074928).

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

64421040 is a wasteful number, since it uses less digits than its factorization.

64421040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3766 (or 3760 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

The square root of 64421040 is about 8026.2718618297. The cubic root of 64421040 is about 400.8752501129.

Adding to 64421040 its reverse (4012446), we get a palindrome (68433486).

The spelling of 64421040 in words is "sixty-four million, four hundred twenty-one thousand, forty".