204221100042 has 64 divisors (see below), whose sum is σ = 470008656000. Its totient is φ = 65651451264.

The previous prime is 204221099983. The next prime is 204221100047. The reversal of 204221100042 is 240001122402.

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

It is a junction number, because it is equal to n+sod(n) for n = 204221099988 and 204221100024.

It is not an unprimeable number, because it can be changed into a prime (204221100047) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1308934 + ... + 1456622.

It is an arithmetic number, because the mean of its divisors is an integer number (7343885250).

Almost surely, 2^204221100042 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 204221100042, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (235004328000).

204221100042 is an abundant number, since it is smaller than the sum of its proper divisors (265787555958).

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

204221100042 is a wasteful number, since it uses less digits than its factorization.

204221100042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148612 (or 148606 counting only the distinct ones).

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

Adding to 204221100042 its reverse (240001122402), we get a palindrome (444222222444).

The spelling of 204221100042 in words is "two hundred four billion, two hundred twenty-one million, one hundred thousand, forty-two".