21064518619 has 4 divisors (see below), whose sum is σ = 21790881360. Its totient is φ = 20338155880.

The previous prime is 21064518589. The next prime is 21064518647. The reversal of 21064518619 is 91681546012.

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

It is not a de Polignac number, because 21064518619 - 2⁹ = 21064518107 is a prime.

It is a super-2 number, since 2×21064518619² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21064518679) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 363181327 + ... + 363181384.

It is an arithmetic number, because the mean of its divisors is an integer number (5447720340).

Almost surely, 2^21064518619 is an apocalyptic number.

21064518619 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21064518619 is a deficient number, since it is larger than the sum of its proper divisors (726362741).

21064518619 is an equidigital number, since it uses as much as digits as its factorization.

21064518619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 726362740.

The product of its (nonzero) digits is 103680, while the sum is 43.

The spelling of 21064518619 in words is "twenty-one billion, sixty-four million, five hundred eighteen thousand, six hundred nineteen".