21123111434 has 16 divisors (see below), whose sum is σ = 31775260608. Its totient is φ = 10531391232.

The previous prime is 21123111391. The next prime is 21123111467. The reversal of 21123111434 is 43411132112.

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, 1433834 + ... + 1448490.

It is an arithmetic number, because the mean of its divisors is an integer number (1985953788).

Almost surely, 2^21123111434 is an apocalyptic number.

21123111434 is a deficient number, since it is larger than the sum of its proper divisors (10652149174).

21123111434 is a wasteful number, since it uses less digits than its factorization.

21123111434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16669.

The product of its digits is 576, while the sum is 23.

Adding to 21123111434 its reverse (43411132112), we get a palindrome (64534243546).

The spelling of 21123111434 in words is "twenty-one billion, one hundred twenty-three million, one hundred eleven thousand, four hundred thirty-four".