21304553117 has 4 divisors (see below), whose sum is σ = 21304898940. Its totient is φ = 21304207296.

The previous prime is 21304553093. The next prime is 21304553131. The reversal of 21304553117 is 71135540312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4566921241 + 16737631876 = 67579^2 + 129374^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21304553117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21304553147) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52598 + ... + 213015.

It is an arithmetic number, because the mean of its divisors is an integer number (5326224735).

Almost surely, 2^21304553117 is an apocalyptic number.

It is an amenable number.

21304553117 is a deficient number, since it is larger than the sum of its proper divisors (345823).

21304553117 is an equidigital number, since it uses as much as digits as its factorization.

21304553117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345822.

The product of its (nonzero) digits is 12600, while the sum is 32.

The spelling of 21304553117 in words is "twenty-one billion, three hundred four million, five hundred fifty-three thousand, one hundred seventeen".