21466502549 has 4 divisors (see below), whose sum is σ = 21469923264. Its totient is φ = 21463081836.

The previous prime is 21466502539. The next prime is 21466502573. The reversal of 21466502549 is 94520566412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21466502549 - 2²⁰ = 21465453973 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 (21466502509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1700927 + ... + 1713500.

It is an arithmetic number, because the mean of its divisors is an integer number (5367480816).

Almost surely, 2^21466502549 is an apocalyptic number.

It is an amenable number.

21466502549 is a deficient number, since it is larger than the sum of its proper divisors (3420715).

21466502549 is an equidigital number, since it uses as much as digits as its factorization.

21466502549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3420714.

The product of its (nonzero) digits is 518400, while the sum is 44.

The spelling of 21466502549 in words is "twenty-one billion, four hundred sixty-six million, five hundred two thousand, five hundred forty-nine".