21606030 has 48 divisors (see below), whose sum is σ = 56407104. Its totient is φ = 5737920.

The previous prime is 21606023. The next prime is 21606037. The reversal of 21606030 is 3060612.

It is a happy number.

21606030 is a `hidden beast` number, since 2 + 1 + 60 + 603 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21606023) and next prime (21606037).

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 = 21605994 and 21606012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21606037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38512 + ... + 39068.

It is an arithmetic number, because the mean of its divisors is an integer number (1175148).

Almost surely, 2^21606030 is an apocalyptic number.

21606030 is an abundant number, since it is smaller than the sum of its proper divisors (34801074).

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

21606030 is a wasteful number, since it uses less digits than its factorization.

21606030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1001 (or 998 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21606030 is about 4648.2286948901. The cubic root of 21606030 is about 278.5212431432.

Adding to 21606030 its reverse (3060612), we get a palindrome (24666642).

It can be divided in two parts, 216060 and 30, that multiplied together give a triangular number (6481800 = T₃₆₀₀).

The spelling of 21606030 in words is "twenty-one million, six hundred six thousand, thirty".