21123110657 has 8 divisors (see below), whose sum is σ = 24398887392. Its totient is φ = 18073249600.

The previous prime is 21123110653. The next prime is 21123110663. The reversal of 21123110657 is 75601132112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21123110657 - 2² = 21123110653 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21123110651) 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, 56478719 + ... + 56479092.

It is an arithmetic number, because the mean of its divisors is an integer number (3049860924).

Almost surely, 2^21123110657 is an apocalyptic number.

It is an amenable number.

21123110657 is a deficient number, since it is larger than the sum of its proper divisors (3275776735).

21123110657 is a wasteful number, since it uses less digits than its factorization.

21123110657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112957839.

The product of its (nonzero) digits is 2520, while the sum is 29.

Adding to 21123110657 its reverse (75601132112), we get a palindrome (96724242769).

The spelling of 21123110657 in words is "twenty-one billion, one hundred twenty-three million, one hundred ten thousand, six hundred fifty-seven".