64727640 has 128 divisors (see below), whose sum is σ = 218980800. Its totient is φ = 17003520.

The previous prime is 64727609. The next prime is 64727651. The reversal of 64727640 is 4672746.

64727640 is a `hidden beast` number, since 6 + 4 + 7 + 2 + 7 + 640 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 64727595 and 64727604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 78430 + ... + 79250.

Almost surely, 2^64727640 is an apocalyptic number.

64727640 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 64727640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109490400).

64727640 is an abundant number, since it is smaller than the sum of its proper divisors (154253160).

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

64727640 is a wasteful number, since it uses less digits than its factorization.

64727640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 914 (or 904 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 36.

The square root of 64727640 is about 8045.3489669498. The cubic root of 64727640 is about 401.5102076729.

The spelling of 64727640 in words is "sixty-four million, seven hundred twenty-seven thousand, six hundred forty".