21640050 has 72 divisors (see below), whose sum is σ = 61223760. Its totient is φ = 5464800.

The previous prime is 21640049. The next prime is 21640063. The reversal of 21640050 is 5004612.

It is a happy number.

21640050 is a `hidden beast` number, since 21 + 640 + 0 + 5 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 7285 + ... + 9815.

It is an arithmetic number, because the mean of its divisors is an integer number (850330).

Almost surely, 2^21640050 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21640050, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30611880).

21640050 is an abundant number, since it is smaller than the sum of its proper divisors (39583710).

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

21640050 is a wasteful number, since it uses less digits than its factorization.

21640050 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2568 (or 2560 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21640050 is about 4651.8867140119. The cubic root of 21640050 is about 278.6673493290.

Adding to 21640050 its reverse (5004612), we get a palindrome (26644662).

The spelling of 21640050 in words is "twenty-one million, six hundred forty thousand, fifty".