121863991 has 2 divisors, whose sum is σ = 121863992. Its totient is φ = 121863990.

The previous prime is 121863983. The next prime is 121864033. The reversal of 121863991 is 199368121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 121863991 - 2³ = 121863983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121863901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60931995 + 60931996.

It is an arithmetic number, because the mean of its divisors is an integer number (60931996).

Almost surely, 2^121863991 is an apocalyptic number.

121863991 is a deficient number, since it is larger than the sum of its proper divisors (1).

121863991 is an equidigital number, since it uses as much as digits as its factorization.

121863991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 40.

The square root of 121863991 is about 11039.2024621347. The cubic root of 121863991 is about 495.7831916969.

The spelling of 121863991 in words is "one hundred twenty-one million, eight hundred sixty-three thousand, nine hundred ninety-one".