64540890864 has 120 divisors (see below), whose sum is σ = 191374157520. Its totient is φ = 20234962944.

The previous prime is 64540890863. The next prime is 64540890877. The reversal of 64540890864 is 46809804546.

64540890864 is a `hidden beast` number, since 6 + 4 + 540 + 8 + 90 + 8 + 6 + 4 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 64540890864.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64540890863) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4175919 + ... + 4191345.

It is an arithmetic number, because the mean of its divisors is an integer number (1594784646).

Almost surely, 2^64540890864 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 64540890864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95687078760).

64540890864 is an abundant number, since it is smaller than the sum of its proper divisors (126833266656).

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

64540890864 is a wasteful number, since it uses less digits than its factorization.

64540890864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17167 (or 17158 counting only the distinct ones).

The product of its (nonzero) digits is 6635520, while the sum is 54.

The spelling of 64540890864 in words is "sixty-four billion, five hundred forty million, eight hundred ninety thousand, eight hundred sixty-four".