649635840 has 576 divisors, whose sum is σ = 2759702400. Its totient is φ = 138018816.

The previous prime is 649635827. The next prime is 649635853. The reversal of 649635840 is 48536946.

649635840 is a `hidden beast` number, since 6 + 4 + 9 + 63 + 584 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (649635827) and next prime (649635853).

It is a tau number, because it is divible by the number of its divisors (576).

It is a super-2 number, since 2×649635840² = 844053449225011200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12257254 + ... + 12257306.

It is an arithmetic number, because the mean of its divisors is an integer number (4791150).

Almost surely, 2^649635840 is an apocalyptic number.

649635840 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 649635840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1379851200).

649635840 is an abundant number, since it is smaller than the sum of its proper divisors (2110066560).

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

649635840 is a wasteful number, since it uses less digits than its factorization.

649635840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112 (or 89 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The square root of 649635840 is about 25487.9548022198. The cubic root of 649635840 is about 866.0773060790.

The spelling of 649635840 in words is "six hundred forty-nine million, six hundred thirty-five thousand, eight hundred forty".