21604030 has 32 divisors (see below), whose sum is σ = 45204480. Its totient is φ = 7280160.

The previous prime is 21604027. The next prime is 21604031. The reversal of 21604030 is 3040612.

It is a super-2 number, since 2×21604030² = 933468224481800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21603995 and 21604013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21604031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1515 + ... + 6745.

It is an arithmetic number, because the mean of its divisors is an integer number (1412640).

Almost surely, 2^21604030 is an apocalyptic number.

21604030 is an abundant number, since it is smaller than the sum of its proper divisors (23600450).

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

21604030 is a wasteful number, since it uses less digits than its factorization.

21604030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5304.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21604030 is about 4648.0135541971. The cubic root of 21604030 is about 278.5126489425.

Adding to 21604030 its reverse (3040612), we get a palindrome (24644642).

The spelling of 21604030 in words is "twenty-one million, six hundred four thousand, thirty".