21031222220731 has 2 divisors, whose sum is σ = 21031222220732. Its totient is φ = 21031222220730.

The previous prime is 21031222220683. The next prime is 21031222220753. The reversal of 21031222220731 is 13702222213012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21031222220731 is a prime.

It is a super-2 number, since 2×21031222220731² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21031222220731.

It is not a weakly prime, because it can be changed into another prime (21031222220791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515611110365 + 10515611110366.

It is an arithmetic number, because the mean of its divisors is an integer number (10515611110366).

Almost surely, 2^{21031222220731} is an apocalyptic number.

21031222220731 is a deficient number, since it is larger than the sum of its proper divisors (1).

21031222220731 is an equidigital number, since it uses as much as digits as its factorization.

21031222220731 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032, while the sum is 28.

Adding to 21031222220731 its reverse (13702222213012), we get a palindrome (34733444433743).

The spelling of 21031222220731 in words is "twenty-one trillion, thirty-one billion, two hundred twenty-two million, two hundred twenty thousand, seven hundred thirty-one".