21201220031 has 2 divisors, whose sum is σ = 21201220032. Its totient is φ = 21201220030.

The previous prime is 21201219997. The next prime is 21201220049. The reversal of 21201220031 is 13002210212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21201220031 - 2¹⁰ = 21201219007 is a prime.

It is a super-2 number, since 2×21201220031² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21201219988 and 21201220015.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201220231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600610015 + 10600610016.

It is an arithmetic number, because the mean of its divisors is an integer number (10600610016).

Almost surely, 2^21201220031 is an apocalyptic number.

21201220031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201220031 is an equidigital number, since it uses as much as digits as its factorization.

21201220031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21201220031 its reverse (13002210212), we get a palindrome (34203430243).

The spelling of 21201220031 in words is "twenty-one billion, two hundred one million, two hundred twenty thousand, thirty-one".