21121320104 has 32 divisors (see below), whose sum is σ = 39744521640. Its totient is φ = 10522828800.

The previous prime is 21121320097. The next prime is 21121320139. The reversal of 21121320104 is 40102312112.

It can be written as a sum of positive squares in 4 ways, for example, as 15575539204 + 5545780900 = 124802^2 + 74470^2 .

It is a super-2 number, since 2×21121320104² (a number of 21 digits) contains 22 as substring.

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, 6100934 + ... + 6104394.

Almost surely, 2^21121320104 is an apocalyptic number.

It is an amenable number.

21121320104 is a deficient number, since it is larger than the sum of its proper divisors (18623201536).

21121320104 is a wasteful number, since it uses less digits than its factorization.

21121320104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5981 (or 5977 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21121320104 its reverse (40102312112), we get a palindrome (61223632216).

The spelling of 21121320104 in words is "twenty-one billion, one hundred twenty-one million, three hundred twenty thousand, one hundred four".