21123316364 has 6 divisors (see below), whose sum is σ = 36965803644. Its totient is φ = 10561658180.

The previous prime is 21123316363. The next prime is 21123316373. The reversal of 21123316364 is 46361332112.

It is a self number, because there is not a number n which added to its sum of digits gives 21123316364.

It is not an unprimeable number, because it can be changed into a prime (21123316363) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640414542 + ... + 2640414549.

It is an arithmetic number, because the mean of its divisors is an integer number (6160967274).

Almost surely, 2^21123316364 is an apocalyptic number.

It is an amenable number.

21123316364 is a deficient number, since it is larger than the sum of its proper divisors (15842487280).

21123316364 is a wasteful number, since it uses less digits than its factorization.

21123316364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5280829095 (or 5280829093 counting only the distinct ones).

The product of its digits is 15552, while the sum is 32.

Adding to 21123316364 its reverse (46361332112), we get a palindrome (67484648476).

The spelling of 21123316364 in words is "twenty-one billion, one hundred twenty-three million, three hundred sixteen thousand, three hundred sixty-four".