64681920 has 168 divisors, whose sum is σ = 228868224. Its totient is φ = 16754688.

The previous prime is 64681913. The next prime is 64681927. The reversal of 64681920 is 2918646.

64681920 is a `hidden beast` number, since 6 + 468 + 192 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (64681913) and next prime (64681927).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64681927) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 106257 + ... + 106863.

Almost surely, 2^64681920 is an apocalyptic number.

64681920 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 64681920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114434112).

64681920 is an abundant number, since it is smaller than the sum of its proper divisors (164186304).

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

64681920 is a wasteful number, since it uses less digits than its factorization.

64681920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 667 (or 654 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 64681920 is about 8042.5070718029. The cubic root of 64681920 is about 401.4156505896.

The spelling of 64681920 in words is "sixty-four million, six hundred eighty-one thousand, nine hundred twenty".