21820216015 has 8 divisors (see below), whose sum is σ = 28198433088. Its totient is φ = 16113390240.

The previous prime is 21820216009. The next prime is 21820216039. The reversal of 21820216015 is 51061202812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21820216015 - 2³ = 21820216007 is a prime.

It is a super-3 number, since 3×21820216015³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 167847751 + ... + 167847880.

It is an arithmetic number, because the mean of its divisors is an integer number (3524804136).

Almost surely, 2^21820216015 is an apocalyptic number.

21820216015 is a deficient number, since it is larger than the sum of its proper divisors (6378217073).

21820216015 is a wasteful number, since it uses less digits than its factorization.

21820216015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335695649.

The product of its (nonzero) digits is 1920, while the sum is 28.

Adding to 21820216015 its reverse (51061202812), we get a palindrome (72881418827).

The spelling of 21820216015 in words is "twenty-one billion, eight hundred twenty million, two hundred sixteen thousand, fifteen".