21073608 has 80 divisors (see below), whose sum is σ = 62530380. Its totient is φ = 6607872.

The previous prime is 21073579. The next prime is 21073627. The reversal of 21073608 is 80637012.

It can be written as a sum of positive squares in 2 ways, for example, as 18507204 + 2566404 = 4302^2 + 1602^2 .

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 10060 + ... + 11972.

Almost surely, 2^21073608 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21073608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31265190).

21073608 is an abundant number, since it is smaller than the sum of its proper divisors (41456772).

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

21073608 is a wasteful number, since it uses less digits than its factorization.

21073608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1948 (or 1935 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21073608 is about 4590.5999607894. The cubic root of 21073608 is about 276.2143891909.

The spelling of 21073608 in words is "twenty-one million, seventy-three thousand, six hundred eight".