21061606 has 24 divisors (see below), whose sum is σ = 34998264. Its totient is φ = 9472320.

The previous prime is 21061603. The next prime is 21061609. The reversal of 21061606 is 60616012.

It is an interprime number because it is at equal distance from previous prime (21061603) and next prime (21061609).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21061603) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17401 + ... + 18571.

It is an arithmetic number, because the mean of its divisors is an integer number (1458261).

Almost surely, 2^21061606 is an apocalyptic number.

21061606 is a deficient number, since it is larger than the sum of its proper divisors (13936658).

21061606 is a wasteful number, since it uses less digits than its factorization.

21061606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1236 (or 1213 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21061606 is about 4589.2925380716. The cubic root of 21061606 is about 276.1619419996.

Adding to 21061606 its reverse (60616012), we get a palindrome (81677618).

It can be divided in two parts, 210 and 61606, that added together give a palindrome (61816).

The spelling of 21061606 in words is "twenty-one million, sixty-one thousand, six hundred six".