21034280 has 32 divisors (see below), whose sum is σ = 48961800. Its totient is φ = 8123136.

The previous prime is 21034261. The next prime is 21034297. The reversal of 21034280 is 8243012.

It can be written as a sum of positive squares in 4 ways, for example, as 16273156 + 4761124 = 4034^2 + 2182^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7907 + ... + 10226.

Almost surely, 2^21034280 is an apocalyptic number.

21034280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21034280 is an abundant number, since it is smaller than the sum of its proper divisors (27927520).

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

21034280 is a wasteful number, since it uses less digits than its factorization.

21034280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18173 (or 18169 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 21034280 is about 4586.3144244589. The cubic root of 21034280 is about 276.0424565366.

Adding to 21034280 its reverse (8243012), we get a palindrome (29277292).

The spelling of 21034280 in words is "twenty-one million, thirty-four thousand, two hundred eighty".