21121230042 has 24 divisors (see below), whose sum is σ = 49922907840. Its totient is φ = 6400372680.

The previous prime is 21121230041. The next prime is 21121230043. The reversal of 21121230042 is 24003212112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21121230041) and next prime (21121230043).

It is a super-2 number, since 2×21121230042² (a number of 21 digits) contains 22 as substring.

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 = 21121229997 and 21121230024.

It is not an unprimeable number, because it can be changed into a prime (21121230041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 53336242 + ... + 53336637.

It is an arithmetic number, because the mean of its divisors is an integer number (2080121160).

Almost surely, 2^21121230042 is an apocalyptic number.

21121230042 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21121230042 is an abundant number, since it is smaller than the sum of its proper divisors (28801677798).

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

21121230042 is a wasteful number, since it uses less digits than its factorization.

21121230042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106672898 (or 106672895 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21121230042 its reverse (24003212112), we get a palindrome (45124442154).

The spelling of 21121230042 in words is "twenty-one billion, one hundred twenty-one million, two hundred thirty thousand, forty-two".