121231210811 has 2 divisors, whose sum is σ = 121231210812. Its totient is φ = 121231210810.

The previous prime is 121231210783. The next prime is 121231210843. The reversal of 121231210811 is 118012132121.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 121231210811 - 2¹⁸ = 121230948667 is a prime.

It is a super-2 number, since 2×121231210811² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (121231212811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60615605405 + 60615605406.

It is an arithmetic number, because the mean of its divisors is an integer number (60615605406).

Almost surely, 2^121231210811 is an apocalyptic number.

121231210811 is a deficient number, since it is larger than the sum of its proper divisors (1).

121231210811 is an equidigital number, since it uses as much as digits as its factorization.

121231210811 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 23.

Adding to 121231210811 its reverse (118012132121), we get a palindrome (239243342932).

The spelling of 121231210811 in words is "one hundred twenty-one billion, two hundred thirty-one million, two hundred ten thousand, eight hundred eleven".