20211639 has 8 divisors (see below), whose sum is σ = 30798720. Its totient is φ = 11549496.

The previous prime is 20211619. The next prime is 20211643. The reversal of 20211639 is 93611202.

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

It is not a de Polignac number, because 20211639 - 2⁹ = 20211127 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211619) 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, 481209 + ... + 481250.

It is an arithmetic number, because the mean of its divisors is an integer number (3849840).

Almost surely, 2^20211639 is an apocalyptic number.

20211639 is a deficient number, since it is larger than the sum of its proper divisors (10587081).

20211639 is an equidigital number, since it uses as much as digits as its factorization.

20211639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 962469.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 20211639 is about 4495.7356461429. The cubic root of 20211639 is about 272.3958651566.

The spelling of 20211639 in words is "twenty million, two hundred eleven thousand, six hundred thirty-nine".