21213404540015 has 16 divisors (see below), whose sum is σ = 25492729342080. Its totient is φ = 16946311656960.

The previous prime is 21213404539993. The next prime is 21213404540059. The reversal of 21213404540015 is 51004540431212.

It is not a de Polignac number, because 21213404540015 - 2³² = 21209109572719 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8750471 + ... + 10908599.

It is an arithmetic number, because the mean of its divisors is an integer number (1593295583880).

Almost surely, 2^{21213404540015} is an apocalyptic number.

21213404540015 is a deficient number, since it is larger than the sum of its proper divisors (4279324802065).

21213404540015 is a wasteful number, since it uses less digits than its factorization.

21213404540015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2160962.

The product of its (nonzero) digits is 19200, while the sum is 32.

Adding to 21213404540015 its reverse (51004540431212), we get a palindrome (72217944971227).

The spelling of 21213404540015 in words is "twenty-one trillion, two hundred thirteen billion, four hundred four million, five hundred forty thousand, fifteen".