21110406005 has 24 divisors (see below), whose sum is σ = 27465833160. Its totient is φ = 15569448960.

The previous prime is 21110405993. The next prime is 21110406049. The reversal of 21110406005 is 50060401112.

It can be written as a sum of positive squares in 12 ways, for example, as 2304672049 + 18805733956 = 48007^2 + 137134^2 .

It is not a de Polignac number, because 21110406005 - 2⁴ = 21110405989 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 668165 + ... + 699045.

It is an arithmetic number, because the mean of its divisors is an integer number (1144409715).

Almost surely, 2^21110406005 is an apocalyptic number.

It is an amenable number.

21110406005 is a deficient number, since it is larger than the sum of its proper divisors (6355427155).

21110406005 is a wasteful number, since it uses less digits than its factorization.

21110406005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31721 (or 31708 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21110406005 its reverse (50060401112), we get a palindrome (71170807117).

The spelling of 21110406005 in words is "twenty-one billion, one hundred ten million, four hundred six thousand, five".