111212121989 has 2 divisors, whose sum is σ = 111212121990. Its totient is φ = 111212121988.

The previous prime is 111212121961. The next prime is 111212122003. The reversal of 111212121989 is 989121212111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72959412100 + 38252709889 = 270110^2 + 195583^2 .

It is a cyclic number.

It is not a de Polignac number, because 111212121989 - 2¹⁶ = 111212056453 is a prime.

It is a super-2 number, since 2×111212121989² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111212121929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55606060994 + 55606060995.

It is an arithmetic number, because the mean of its divisors is an integer number (55606060995).

Almost surely, 2^111212121989 is an apocalyptic number.

It is an amenable number.

111212121989 is a deficient number, since it is larger than the sum of its proper divisors (1).

111212121989 is an equidigital number, since it uses as much as digits as its factorization.

111212121989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 38.

The spelling of 111212121989 in words is "one hundred eleven billion, two hundred twelve million, one hundred twenty-one thousand, nine hundred eighty-nine".