64540421620 has 96 divisors (see below), whose sum is σ = 144230284800. Its totient is φ = 24218686464.

The previous prime is 64540421599. The next prime is 64540421683. The reversal of 64540421620 is 2612404546.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3780624 + ... + 3797656.

It is an arithmetic number, because the mean of its divisors is an integer number (1502398800).

Almost surely, 2^64540421620 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64540421620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72115142400).

64540421620 is an abundant number, since it is smaller than the sum of its proper divisors (79689863180).

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

64540421620 is a wasteful number, since it uses less digits than its factorization.

64540421620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17257 (or 17255 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 34.

The spelling of 64540421620 in words is "sixty-four billion, five hundred forty million, four hundred twenty-one thousand, six hundred twenty".