21384961765 has 8 divisors (see below), whose sum is σ = 25662742560. Its totient is φ = 17107443792.

The previous prime is 21384961751. The next prime is 21384961769. The reversal of 21384961765 is 56716948312.

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 21384961765 - 2⁵ = 21384961733 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21384961769) 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, 260926 + ... + 332944.

It is an arithmetic number, because the mean of its divisors is an integer number (3207842820).

Almost surely, 2^21384961765 is an apocalyptic number.

It is an amenable number.

21384961765 is a deficient number, since it is larger than the sum of its proper divisors (4277780795).

21384961765 is an equidigital number, since it uses as much as digits as its factorization.

21384961765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131411.

The product of its digits is 2177280, while the sum is 52.

The spelling of 21384961765 in words is "twenty-one billion, three hundred eighty-four million, nine hundred sixty-one thousand, seven hundred sixty-five".