21131220411 has 32 divisors (see below), whose sum is σ = 36208811520. Its totient is φ = 11929492512.

The previous prime is 21131220361. The next prime is 21131220413. The reversal of 21131220411 is 11402213112.

21131220411 is a `hidden beast` number, since 2 + 1 + 1 + 31 + 220 + 411 = 666.

It is not a de Polignac number, because 21131220411 - 2¹¹ = 21131218363 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21131220413) 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, 657840 + ... + 689213.

It is an arithmetic number, because the mean of its divisors is an integer number (1131525360).

Almost surely, 2^21131220411 is an apocalyptic number.

21131220411 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21131220411 is a deficient number, since it is larger than the sum of its proper divisors (15077591109).

21131220411 is a wasteful number, since it uses less digits than its factorization.

21131220411 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1347152 (or 1347146 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 21131220411 its reverse (11402213112), we get a palindrome (32533433523).

The spelling of 21131220411 in words is "twenty-one billion, one hundred thirty-one million, two hundred twenty thousand, four hundred eleven".