20421686 has 8 divisors (see below), whose sum is σ = 30697920. Its totient is φ = 10189048.

The previous prime is 20421647. The next prime is 20421691. The reversal of 20421686 is 68612402.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9701 + ... + 11616.

It is an arithmetic number, because the mean of its divisors is an integer number (3837240).

Almost surely, 2^20421686 is an apocalyptic number.

20421686 is a deficient number, since it is larger than the sum of its proper divisors (10276234).

20421686 is a wasteful number, since it uses less digits than its factorization.

20421686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21798.

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 20421686 is about 4519.0359591400. The cubic root of 20421686 is about 273.3362287353.

The spelling of 20421686 in words is "twenty million, four hundred twenty-one thousand, six hundred eighty-six".