21709050 has 96 divisors (see below), whose sum is σ = 59996160. Its totient is φ = 5150400.

The previous prime is 21709027. The next prime is 21709063. The reversal of 21709050 is 5090712.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21709050.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 97239 + ... + 97461.

It is an arithmetic number, because the mean of its divisors is an integer number (624960).

Almost surely, 2^21709050 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21709050, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29998080).

21709050 is an abundant number, since it is smaller than the sum of its proper divisors (38287110).

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

21709050 is a wasteful number, since it uses less digits than its factorization.

21709050 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308 (or 303 counting only the distinct ones).

The product of its (nonzero) digits is 630, while the sum is 24.

The square root of 21709050 is about 4659.2971572974. The cubic root of 21709050 is about 278.9632150472.

Adding to 21709050 its reverse (5090712), we get a palindrome (26799762).

The spelling of 21709050 in words is "twenty-one million, seven hundred nine thousand, fifty".