64542861990 has 64 divisors (see below), whose sum is σ = 172375948800. Its totient is φ = 17185264992.

The previous prime is 64542861989. The next prime is 64542861991. The reversal of 64542861990 is 9916824546.

64542861990 is a `hidden beast` number, since 6 + 4 + 542 + 8 + 6 + 1 + 9 + 90 = 666.

It is an interprime number because it is at equal distance from previous prime (64542861989) and next prime (64542861991).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64542861991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3442 + ... + 359301.

It is an arithmetic number, because the mean of its divisors is an integer number (2693374200).

Almost surely, 2^64542861990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64542861990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86187974400).

64542861990 is an abundant number, since it is smaller than the sum of its proper divisors (107833086810).

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

64542861990 is a wasteful number, since it uses less digits than its factorization.

64542861990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363418 (or 363412 counting only the distinct ones).

The product of its (nonzero) digits is 3732480, while the sum is 54.

The spelling of 64542861990 in words is "sixty-four billion, five hundred forty-two million, eight hundred sixty-one thousand, nine hundred ninety".