21111153442 has 4 divisors (see below), whose sum is σ = 31666730166. Its totient is φ = 10555576720.

The previous prime is 21111153407. The next prime is 21111153449. The reversal of 21111153442 is 24435111112.

It is a happy number.

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., 19645105921 + 1466047521 = 140161^2 + 38289^2 .

It is not an unprimeable number, because it can be changed into a prime (21111153449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5277788359 + ... + 5277788362.

Almost surely, 2^21111153442 is an apocalyptic number.

21111153442 is a deficient number, since it is larger than the sum of its proper divisors (10555576724).

21111153442 is a wasteful number, since it uses less digits than its factorization.

21111153442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10555576723.

The product of its digits is 960, while the sum is 25.

Adding to 21111153442 its reverse (24435111112), we get a palindrome (45546264554).

The spelling of 21111153442 in words is "twenty-one billion, one hundred eleven million, one hundred fifty-three thousand, four hundred forty-two".