21110131421 has 4 divisors (see below), whose sum is σ = 21127827612. Its totient is φ = 21092435232.

The previous prime is 21110131417. The next prime is 21110131447. The reversal of 21110131421 is 12413101112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7424407225 + 13685724196 = 86165^2 + 116986^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110131421 - 2² = 21110131417 is a prime.

It is a super-2 number, since 2×21110131421² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21110131421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110131321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8846306 + ... + 8848691.

It is an arithmetic number, because the mean of its divisors is an integer number (5281956903).

Almost surely, 2^21110131421 is an apocalyptic number.

It is an amenable number.

21110131421 is a deficient number, since it is larger than the sum of its proper divisors (17696191).

21110131421 is a wasteful number, since it uses less digits than its factorization.

21110131421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17696190.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 21110131421 its reverse (12413101112), we get a palindrome (33523232533).

The spelling of 21110131421 in words is "twenty-one billion, one hundred ten million, one hundred thirty-one thousand, four hundred twenty-one".