65810899440 has 1600 divisors, whose sum is σ = 290381414400. Its totient is φ = 13586227200.

The previous prime is 65810899423. The next prime is 65810899459. The reversal of 65810899440 is 4499801856.

65810899440 is a `hidden beast` number, since 6 + 5 + 8 + 108 + 99 + 440 = 666.

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

It is a congruent number.

It is an unprimeable number.

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 319 ways as a sum of consecutive naturals, for example, 833049321 + ... + 833049399.

It is an arithmetic number, because the mean of its divisors is an integer number (181488384).

Almost surely, 2^65810899440 is an apocalyptic number.

65810899440 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 65810899440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145190707200).

65810899440 is an abundant number, since it is smaller than the sum of its proper divisors (224570514960).

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

65810899440 is a wasteful number, since it uses less digits than its factorization.

65810899440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188 (or 173 counting only the distinct ones).

The product of its (nonzero) digits is 2488320, while the sum is 54.

The spelling of 65810899440 in words is "sixty-five billion, eight hundred ten million, eight hundred ninety-nine thousand, four hundred forty".