643748280 has 96 divisors (see below), whose sum is σ = 2246570640. Its totient is φ = 147141120.

The previous prime is 643748251. The next prime is 643748309. The reversal of 643748280 is 82847346.

It is an interprime number because it is at equal distance from previous prime (643748251) and next prime (643748309).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 48861 + ... + 60620.

Almost surely, 2^643748280 is an apocalyptic number.

643748280 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643748280 is an abundant number, since it is smaller than the sum of its proper divisors (1602822360).

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

643748280 is a wasteful number, since it uses less digits than its factorization.

643748280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109509 (or 109498 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 42.

The square root of 643748280 is about 25372.1950173807. The cubic root of 643748280 is about 863.4529823620.

The spelling of 643748280 in words is "six hundred forty-three million, seven hundred forty-eight thousand, two hundred eighty".