643749498 has 32 divisors (see below), whose sum is σ = 1634920320. Its totient is φ = 183928320.

The previous prime is 643749481. The next prime is 643749539. The reversal of 643749498 is 894947346.

It is a happy number.

643749498 is a `hidden beast` number, since 64 + 3 + 7 + 494 + 98 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 851143 + ... + 851898.

It is an arithmetic number, because the mean of its divisors is an integer number (51091260).

Almost surely, 2^643749498 is an apocalyptic number.

643749498 is an abundant number, since it is smaller than the sum of its proper divisors (991170822).

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

643749498 is a wasteful number, since it uses less digits than its factorization.

643749498 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1703059 (or 1703053 counting only the distinct ones).

The product of its digits is 5225472, while the sum is 54.

The square root of 643749498 is about 25372.2190200227. The cubic root of 643749498 is about 863.4535269253.

The spelling of 643749498 in words is "six hundred forty-three million, seven hundred forty-nine thousand, four hundred ninety-eight".