21256755863 has 8 divisors (see below), whose sum is σ = 24296039328. Its totient is φ = 18218123424.

The previous prime is 21256755803. The next prime is 21256755869. The reversal of 21256755863 is 36855765212.

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 21256755863 - 2¹² = 21256751767 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 (21256755869) 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, 90656 + ... + 225237.

It is an arithmetic number, because the mean of its divisors is an integer number (3037004916).

Almost surely, 2^21256755863 is an apocalyptic number.

21256755863 is a deficient number, since it is larger than the sum of its proper divisors (3039283465).

21256755863 is an equidigital number, since it uses as much as digits as its factorization.

21256755863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325513.

The product of its digits is 3024000, while the sum is 50.

The spelling of 21256755863 in words is "twenty-one billion, two hundred fifty-six million, seven hundred fifty-five thousand, eight hundred sixty-three".