1640138 has 8 divisors (see below), whose sum is σ = 2506788. Its totient is φ = 804544.

The previous prime is 1640131. The next prime is 1640147. The reversal of 1640138 is 8310461.

It can be written as a sum of positive squares in 2 ways, for example, as 1630729 + 9409 = 1277^2 + 97^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (1640131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7631 + ... + 7842.

2^1640138 is an apocalyptic number.

1640138 is a deficient number, since it is larger than the sum of its proper divisors (866650).

1640138 is a wasteful number, since it uses less digits than its factorization.

1640138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15528.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 1640138 is about 1280.6787263010. The cubic root of 1640138 is about 117.9306784256.

Adding to 1640138 its reverse (8310461), we get a palindrome (9950599).

The spelling of 1640138 in words is "one million, six hundred forty thousand, one hundred thirty-eight".