21122120993 has 2 divisors, whose sum is σ = 21122120994. Its totient is φ = 21122120992.

The previous prime is 21122120989. The next prime is 21122121017. The reversal of 21122120993 is 39902122112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21081007249 + 41113744 = 145193^2 + 6412^2 .

It is a cyclic number.

It is not a de Polignac number, because 21122120993 - 2² = 21122120989 is a prime.

It is a super-2 number, since 2×21122120993² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21122120923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561060496 + 10561060497.

It is an arithmetic number, because the mean of its divisors is an integer number (10561060497).

Almost surely, 2^21122120993 is an apocalyptic number.

It is an amenable number.

21122120993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122120993 is an equidigital number, since it uses as much as digits as its factorization.

21122120993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 32.

The spelling of 21122120993 in words is "twenty-one billion, one hundred twenty-two million, one hundred twenty thousand, nine hundred ninety-three".