20010121993 has 2 divisors, whose sum is σ = 20010121994. Its totient is φ = 20010121992.

The previous prime is 20010121973. The next prime is 20010121997. The reversal of 20010121993 is 39912101002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12018298384 + 7991823609 = 109628^2 + 89397^2 .

It is a cyclic number.

It is not a de Polignac number, because 20010121993 - 2⁵ = 20010121961 is a prime.

It is not a weakly prime, because it can be changed into another prime (20010121997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10005060996 + 10005060997.

It is an arithmetic number, because the mean of its divisors is an integer number (10005060997).

Almost surely, 2^20010121993 is an apocalyptic number.

It is an amenable number.

20010121993 is a deficient number, since it is larger than the sum of its proper divisors (1).

20010121993 is an equidigital number, since it uses as much as digits as its factorization.

20010121993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 28.

Adding to 20010121993 its reverse (39912101002), we get a palindrome (59922222995).

The spelling of 20010121993 in words is "twenty billion, ten million, one hundred twenty-one thousand, nine hundred ninety-three".