21529581819 has 4 divisors (see below), whose sum is σ = 28706109096. Its totient is φ = 14353054544.

The previous prime is 21529581803. The next prime is 21529581833. The reversal of 21529581819 is 91818592512.

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

It is a cyclic number.

It is not a de Polignac number, because 21529581819 - 2⁴ = 21529581803 is a prime.

It is a super-2 number, since 2×21529581819² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21529581839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3588263634 + ... + 3588263639.

It is an arithmetic number, because the mean of its divisors is an integer number (7176527274).

Almost surely, 2^21529581819 is an apocalyptic number.

21529581819 is a deficient number, since it is larger than the sum of its proper divisors (7176527277).

21529581819 is an equidigital number, since it uses as much as digits as its factorization.

21529581819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7176527276.

The product of its digits is 518400, while the sum is 51.

The spelling of 21529581819 in words is "twenty-one billion, five hundred twenty-nine million, five hundred eighty-one thousand, eight hundred nineteen".