21621412231215 has 32 divisors (see below), whose sum is σ = 34898333502720. Its totient is φ = 11430435211776.

The previous prime is 21621412231213. The next prime is 21621412231241. The reversal of 21621412231215 is 51213221412612.

It is not a de Polignac number, because 21621412231215 - 2¹ = 21621412231213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621412231213) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10739722 + ... + 12593031.

It is an arithmetic number, because the mean of its divisors is an integer number (1090572921960).

Almost surely, 2^{21621412231215} is an apocalyptic number.

21621412231215 is a deficient number, since it is larger than the sum of its proper divisors (13276921271505).

21621412231215 is a wasteful number, since it uses less digits than its factorization.

21621412231215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23333303.

The product of its digits is 11520, while the sum is 33.

Adding to 21621412231215 its reverse (51213221412612), we get a palindrome (72834633643827).

The spelling of 21621412231215 in words is "twenty-one trillion, six hundred twenty-one billion, four hundred twelve million, two hundred thirty-one thousand, two hundred fifteen".