21144122542 has 16 divisors (see below), whose sum is σ = 31761590400. Its totient is φ = 10556939448.

The previous prime is 21144122537. The next prime is 21144122543. The reversal of 21144122542 is 24522144112.

It is a super-2 number, since 2×21144122542² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21144122542.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144122543) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7809553 + ... + 7812259.

It is an arithmetic number, because the mean of its divisors is an integer number (1985099400).

Almost surely, 2^21144122542 is an apocalyptic number.

21144122542 is a deficient number, since it is larger than the sum of its proper divisors (10617467858).

21144122542 is a wasteful number, since it uses less digits than its factorization.

21144122542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6855.

The product of its digits is 5120, while the sum is 28.

Adding to 21144122542 its reverse (24522144112), we get a palindrome (45666266654).

The spelling of 21144122542 in words is "twenty-one billion, one hundred forty-four million, one hundred twenty-two thousand, five hundred forty-two".