1965638 has 4 divisors (see below), whose sum is σ = 2948460. Its totient is φ = 982818.

The previous prime is 1965637. The next prime is 1965641. The reversal of 1965638 is 8365691.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1965631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 491408 + ... + 491411.

It is an arithmetic number, because the mean of its divisors is an integer number (737115).

2^1965638 is an apocalyptic number.

1965638 is a deficient number, since it is larger than the sum of its proper divisors (982822).

1965638 is an equidigital number, since it uses as much as digits as its factorization.

1965638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 982821.

The product of its digits is 38880, while the sum is 38.

The square root of 1965638 is about 1402.0121254825. The cubic root of 1965638 is about 125.2663759476.

The spelling of 1965638 in words is "one million, nine hundred sixty-five thousand, six hundred thirty-eight".