21802418042 has 4 divisors (see below), whose sum is σ = 32703627066. Its totient is φ = 10901209020.

The previous prime is 21802418039. The next prime is 21802418047. The reversal of 21802418042 is 24081420812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20597703361 + 1204714681 = 143519^2 + 34709^2 .

It is a super-2 number, since 2×21802418042² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21802418047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5450604509 + ... + 5450604512.

Almost surely, 2^21802418042 is an apocalyptic number.

21802418042 is a deficient number, since it is larger than the sum of its proper divisors (10901209024).

21802418042 is a wasteful number, since it uses less digits than its factorization.

21802418042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10901209023.

The product of its (nonzero) digits is 8192, while the sum is 32.

Adding to 21802418042 its reverse (24081420812), we get a palindrome (45883838854).

The spelling of 21802418042 in words is "twenty-one billion, eight hundred two million, four hundred eighteen thousand, forty-two".