642021738 has 16 divisors (see below), whose sum is σ = 1303209120. Its totient is φ = 210812976.

The previous prime is 642021719. The next prime is 642021781. The reversal of 642021738 is 837120246.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 642021699 and 642021708.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 798133 + ... + 798936.

It is an arithmetic number, because the mean of its divisors is an integer number (81450570).

Almost surely, 2^642021738 is an apocalyptic number.

642021738 is an abundant number, since it is smaller than the sum of its proper divisors (661187382).

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

642021738 is a wasteful number, since it uses less digits than its factorization.

642021738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1597141.

The product of its (nonzero) digits is 16128, while the sum is 33.

The square root of 642021738 is about 25338.1478802220. The cubic root of 642021738 is about 862.6803601813.

The spelling of 642021738 in words is "six hundred forty-two million, twenty-one thousand, seven hundred thirty-eight".