64581820 has 12 divisors (see below), whose sum is σ = 135621864. Its totient is φ = 25832720.

The previous prime is 64581799. The next prime is 64581833. The reversal of 64581820 is 2818546.

It is a super-2 number, since 2×64581820² = 8341622949024800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1614526 + ... + 1614565.

It is an arithmetic number, because the mean of its divisors is an integer number (11301822).

Almost surely, 2^64581820 is an apocalyptic number.

It is an amenable number.

64581820 is an abundant number, since it is smaller than the sum of its proper divisors (71040044).

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

64581820 is a wasteful number, since it uses less digits than its factorization.

64581820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3229100 (or 3229098 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 34.

The square root of 64581820 is about 8036.2814783953. The cubic root of 64581820 is about 401.2084703219.

The spelling of 64581820 in words is "sixty-four million, five hundred eighty-one thousand, eight hundred twenty".