21008034 has 72 divisors (see below), whose sum is σ = 49747932. Its totient is φ = 6402240.

The previous prime is 21008027. The next prime is 21008041. The reversal of 21008034 is 43080012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21008027) and next prime (21008041).

It can be written as a sum of positive squares in 2 ways, for example, as 20277009 + 731025 = 4503^2 + 855^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21007998 and 21008016.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 344364 + ... + 344424.

Almost surely, 2^21008034 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21008034, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24873966).

21008034 is an abundant number, since it is smaller than the sum of its proper divisors (28739898).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21008034 is a wasteful number, since it uses less digits than its factorization.

21008034 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160 (or 138 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21008034 is about 4583.4521923982. The cubic root of 21008034 is about 275.9275960045.

Adding to 21008034 its reverse (43080012), we get a palindrome (64088046).

The spelling of 21008034 in words is "twenty-one million, eight thousand, thirty-four".