64690920 has 256 divisors, whose sum is σ = 253440000. Its totient is φ = 14370048.

The previous prime is 64690903. The next prime is 64690939. The reversal of 64690920 is 2909646.

64690920 is a `hidden beast` number, since 646 + 9 + 0 + 9 + 2 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 324981 + ... + 325179.

It is an arithmetic number, because the mean of its divisors is an integer number (990000).

Almost surely, 2^64690920 is an apocalyptic number.

64690920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

64690920 is the 4644-th octagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64690920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126720000).

64690920 is an abundant number, since it is smaller than the sum of its proper divisors (188749080).

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

64690920 is a wasteful number, since it uses less digits than its factorization.

64690920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269 (or 259 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The square root of 64690920 is about 8043.0665793589. The cubic root of 64690920 is about 401.4342677102.

The spelling of 64690920 in words is "sixty-four million, six hundred ninety thousand, nine hundred twenty".