21221242031 has 16 divisors (see below), whose sum is σ = 24253302528. Its totient is φ = 18379680000.

The previous prime is 21221242019. The next prime is 21221242033. The reversal of 21221242031 is 13024212212.

It is not a de Polignac number, because 21221242031 - 2²⁶ = 21154133167 is a prime.

It is a super-2 number, since 2×21221242031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21221241994 and 21221242012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221242033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 103586 + ... + 230591.

It is an arithmetic number, because the mean of its divisors is an integer number (1515831408).

Almost surely, 2^21221242031 is an apocalyptic number.

21221242031 is a deficient number, since it is larger than the sum of its proper divisors (3032060497).

21221242031 is a wasteful number, since it uses less digits than its factorization.

21221242031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334462.

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 21221242031 its reverse (13024212212), we get a palindrome (34245454243).

The spelling of 21221242031 in words is "twenty-one billion, two hundred twenty-one million, two hundred forty-two thousand, thirty-one".