20421008 has 10 divisors (see below), whose sum is σ = 39565734. Its totient is φ = 10210496.

The previous prime is 20420999. The next prime is 20421013. The reversal of 20421008 is 80012402.

It can be written as a sum of positive squares in only one way, i.e., 12759184 + 7661824 = 3572^2 + 2768^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 638141 + ... + 638172.

Almost surely, 2^20421008 is an apocalyptic number.

It is an amenable number.

20421008 is a deficient number, since it is larger than the sum of its proper divisors (19144726).

20421008 is a wasteful number, since it uses less digits than its factorization.

20421008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1276321 (or 1276315 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 20421008 is about 4518.9609425176. The cubic root of 20421008 is about 273.3332037808. Note that the first 3 decimals are identical.

It can be divided in two parts, 204 and 21008, that added together give a palindrome (21212).

The spelling of 20421008 in words is "twenty million, four hundred twenty-one thousand, eight".