64981800 has 144 divisors (see below), whose sum is σ = 235102140. Its totient is φ = 15989760.

The previous prime is 64981799. The next prime is 64981811. The reversal of 64981800 is 818946.

It is a happy number.

64981800 is a `hidden beast` number, since 649 + 8 + 1 + 8 + 0 + 0 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 4235364 + 60746436 = 2058^2 + 7794^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 22012 + ... + 24788.

Almost surely, 2^64981800 is an apocalyptic number.

64981800 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 64981800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117551070).

64981800 is an abundant number, since it is smaller than the sum of its proper divisors (170120340).

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

64981800 is a wasteful number, since it uses less digits than its factorization.

64981800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2812 (or 2800 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 64981800 is about 8061.1289531926. The cubic root of 64981800 is about 402.0350455821.

It can be divided in two parts, 6498 and 1800, that multiplied together give a square (11696400 = 3420²).

The spelling of 64981800 in words is "sixty-four million, nine hundred eighty-one thousand, eight hundred".