643749942 has 16 divisors (see below), whose sum is σ = 1404545472. Its totient is φ = 195075720.

The previous prime is 643749941. The next prime is 643749959. The reversal of 643749942 is 249947346.

It is a junction number, because it is equal to n+sod(n) for n = 643749891 and 643749900.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643749941) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4876828 + ... + 4876959.

It is an arithmetic number, because the mean of its divisors is an integer number (87784092).

Almost surely, 2^643749942 is an apocalyptic number.

643749942 is an abundant number, since it is smaller than the sum of its proper divisors (760795530).

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

643749942 is a wasteful number, since it uses less digits than its factorization.

643749942 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9753803.

The product of its digits is 1306368, while the sum is 48.

The square root of 643749942 is about 25372.2277697486. The cubic root of 643749942 is about 863.4537254359.

The spelling of 643749942 in words is "six hundred forty-three million, seven hundred forty-nine thousand, nine hundred forty-two".