646978752 has 294 divisors, whose sum is σ = 2247072468. Its totient is φ = 184197888.

The previous prime is 646978751. The next prime is 646978771. The reversal of 646978752 is 257879646.

It is a tau number, because it is divible by the number of its divisors (294).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (646978751) by changing a digit.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 2286003 + ... + 2286285.

Almost surely, 2^646978752 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646978752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1123536234).

646978752 is an abundant number, since it is smaller than the sum of its proper divisors (1600093716).

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

646978752 is an equidigital number, since it uses as much as digits as its factorization.

646978752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327 (or 295 counting only the distinct ones).

The product of its digits is 5080320, while the sum is 54.

The square root of 646978752 is about 25435.7770079862. Note that the first 3 decimals coincide. The cubic root of 646978752 is about 864.8949060956.

The spelling of 646978752 in words is "six hundred forty-six million, nine hundred seventy-eight thousand, seven hundred fifty-two".