21202100442 has 24 divisors (see below), whose sum is σ = 47935184544. Its totient is φ = 6760089864.

The previous prime is 21202100431. The next prime is 21202100449. The reversal of 21202100442 is 24400120212.

21202100442 is a `hidden beast` number, since 2 + 12 + 0 + 210 + 0 + 442 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (21202100449) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25605988 + ... + 25606815.

It is an arithmetic number, because the mean of its divisors is an integer number (1997299356).

Almost surely, 2^21202100442 is an apocalyptic number.

21202100442 is an abundant number, since it is smaller than the sum of its proper divisors (26733084102).

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

21202100442 is a wasteful number, since it uses less digits than its factorization.

21202100442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51212834 (or 51212831 counting only the distinct ones).

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

Adding to 21202100442 its reverse (24400120212), we get a palindrome (45602220654).

The spelling of 21202100442 in words is "twenty-one billion, two hundred two million, one hundred thousand, four hundred forty-two".