21626730 has 64 divisors (see below), whose sum is σ = 58129920. Its totient is φ = 5721408.

The previous prime is 21626719. The next prime is 21626743. The reversal of 21626730 is 3762612.

It is a happy number.

21626730 is a `hidden beast` number, since 2 + 1 + 626 + 7 + 30 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21626694 and 21626703.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 46479 + ... + 46941.

It is an arithmetic number, because the mean of its divisors is an integer number (908280).

Almost surely, 2^21626730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21626730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29064960).

21626730 is an abundant number, since it is smaller than the sum of its proper divisors (36503190).

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

21626730 is a wasteful number, since it uses less digits than its factorization.

21626730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 652 (or 646 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 27.

The square root of 21626730 is about 4650.4548164669. The cubic root of 21626730 is about 278.6101619852.

The spelling of 21626730 in words is "twenty-one million, six hundred twenty-six thousand, seven hundred thirty".