21305355247 has 8 divisors (see below), whose sum is σ = 24609394512. Its totient is φ = 18229180800.

The previous prime is 21305355229. The next prime is 21305355283. The reversal of 21305355247 is 74255350312.

It is a happy number.

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 21305355247 - 2⁷ = 21305355119 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 (21305355217) 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, 56966004 + ... + 56966377.

It is an arithmetic number, because the mean of its divisors is an integer number (3076174314).

Almost surely, 2^21305355247 is an apocalyptic number.

21305355247 is a deficient number, since it is larger than the sum of its proper divisors (3304039265).

21305355247 is a wasteful number, since it uses less digits than its factorization.

21305355247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113932409.

The product of its (nonzero) digits is 126000, while the sum is 37.

The spelling of 21305355247 in words is "twenty-one billion, three hundred five million, three hundred fifty-five thousand, two hundred forty-seven".