21004234042 has 16 divisors (see below), whose sum is σ = 34416850752. Its totient is φ = 9534521920.

The previous prime is 21004234033. The next prime is 21004234051. The reversal of 21004234042 is 24043240012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21004234033) and next prime (21004234051).

It is a super-2 number, since 2×21004234042² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 626143 + ... + 658834.

It is an arithmetic number, because the mean of its divisors is an integer number (2151053172).

Almost surely, 2^21004234042 is an apocalyptic number.

21004234042 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21004234042 is a deficient number, since it is larger than the sum of its proper divisors (13412616710).

21004234042 is a wasteful number, since it uses less digits than its factorization.

21004234042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1285733.

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 21004234042 its reverse (24043240012), we get a palindrome (45047474054).

The spelling of 21004234042 in words is "twenty-one billion, four million, two hundred thirty-four thousand, forty-two".