21210004242 has 96 divisors (see below), whose sum is σ = 54170049024. Its totient is φ = 5872176000.

The previous prime is 21210004187. The next prime is 21210004261. The reversal of 21210004242 is 24240001212.

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 47 ways as a sum of consecutive naturals, for example, 580392 + ... + 615852.

It is an arithmetic number, because the mean of its divisors is an integer number (564271344).

Almost surely, 2^21210004242 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21210004242, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27085024512).

21210004242 is an abundant number, since it is smaller than the sum of its proper divisors (32960044782).

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

21210004242 is a wasteful number, since it uses less digits than its factorization.

21210004242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35624 (or 35621 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 21210004242 its reverse (24240001212), we get a palindrome (45450005454).

The spelling of 21210004242 in words is "twenty-one billion, two hundred ten million, four thousand, two hundred forty-two".