21612120420304 has 40 divisors (see below), whose sum is σ = 42020475229512. Its totient is φ = 10768168181760.

The previous prime is 21612120420301. The next prime is 21612120420323. The reversal of 21612120420304 is 40302402121612.

It can be written as a sum of positive squares in 4 ways, for example, as 3041605760400 + 18570514659904 = 1744020^2 + 4309352^2 .

It is a super-2 number, since 2×21612120420304² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21612120420301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7072822 + ... + 9656554.

Almost surely, 2^{21612120420304} is an apocalyptic number.

It is an amenable number.

21612120420304 is a deficient number, since it is larger than the sum of its proper divisors (20408354809208).

21612120420304 is a wasteful number, since it uses less digits than its factorization.

21612120420304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2585575 (or 2585569 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

Adding to 21612120420304 its reverse (40302402121612), we get a palindrome (61914522541916).

The spelling of 21612120420304 in words is "twenty-one trillion, six hundred twelve billion, one hundred twenty million, four hundred twenty thousand, three hundred four".