21810734257 has 8 divisors (see below), whose sum is σ = 23491488384. Its totient is φ = 20130409488.

The previous prime is 21810734251. The next prime is 21810734269. The reversal of 21810734257 is 75243701812.

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 21810734257 - 2⁷ = 21810734129 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21810734251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2328 + ... + 208870.

It is an arithmetic number, because the mean of its divisors is an integer number (2936436048).

Almost surely, 2^21810734257 is an apocalyptic number.

It is an amenable number.

21810734257 is a deficient number, since it is larger than the sum of its proper divisors (1680754127).

21810734257 is a wasteful number, since it uses less digits than its factorization.

21810734257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214679.

The product of its (nonzero) digits is 94080, while the sum is 40.

The spelling of 21810734257 in words is "twenty-one billion, eight hundred ten million, seven hundred thirty-four thousand, two hundred fifty-seven".