21766650 has 72 divisors (see below), whose sum is σ = 56148192. Its totient is φ = 5580000.

The previous prime is 21766649. The next prime is 21766651. The reversal of 21766650 is 5666712.

It is an interprime number because it is at equal distance from previous prime (21766649) and next prime (21766651).

It is not an unprimeable number, because it can be changed into a prime (21766651) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 144075 + ... + 144225.

It is an arithmetic number, because the mean of its divisors is an integer number (779836).

Almost surely, 2^21766650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21766650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28074096).

21766650 is an abundant number, since it is smaller than the sum of its proper divisors (34381542).

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

21766650 is a wasteful number, since it uses less digits than its factorization.

21766650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228 (or 192 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 21766650 is about 4665.4742524206. The cubic root of 21766650 is about 279.2097188621.

The spelling of 21766650 in words is "twenty-one million, seven hundred sixty-six thousand, six hundred fifty".