1213639 has 8 divisors (see below), whose sum is σ = 1394208. Its totient is φ = 1034880.

The previous prime is 1213633. The next prime is 1213643. The reversal of 1213639 is 9363121.

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

It is not a de Polignac number, because 1213639 - 2³ = 1213631 is a prime.

It is a Duffinian number.

1213639 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213631) 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, 1659 + ... + 2275.

It is an arithmetic number, because the mean of its divisors is an integer number (174276).

2^1213639 is an apocalyptic number.

1213639 is a deficient number, since it is larger than the sum of its proper divisors (180569).

1213639 is an equidigital number, since it uses as much as digits as its factorization.

1213639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 905.

The product of its digits is 972, while the sum is 25.

The square root of 1213639 is about 1101.6528491317. The cubic root of 1213639 is about 106.6669411885. Note that the first 3 decimals are identical.

The spelling of 1213639 in words is "one million, two hundred thirteen thousand, six hundred thirty-nine".