21768606 has 12 divisors (see below), whose sum is σ = 47165352. Its totient is φ = 7256196.

The previous prime is 21768601. The next prime is 21768611. The reversal of 21768606 is 60686712.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21768601) and next prime (21768611).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21768601) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 604666 + ... + 604701.

It is an arithmetic number, because the mean of its divisors is an integer number (3930446).

Almost surely, 2^21768606 is an apocalyptic number.

21768606 is an abundant number, since it is smaller than the sum of its proper divisors (25396746).

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

21768606 is a wasteful number, since it uses less digits than its factorization.

21768606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1209375 (or 1209372 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 21768606 is about 4665.6838727029. The cubic root of 21768606 is about 279.2180820822.

The spelling of 21768606 in words is "twenty-one million, seven hundred sixty-eight thousand, six hundred six".