120820991 has 2 divisors, whose sum is σ = 120820992. Its totient is φ = 120820990.

The previous prime is 120820963. The next prime is 120821003. The reversal of 120820991 is 199028021.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 120820991 - 2²² = 116626687 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (120820901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60410495 + 60410496.

It is an arithmetic number, because the mean of its divisors is an integer number (60410496).

Almost surely, 2^120820991 is an apocalyptic number.

120820991 is a deficient number, since it is larger than the sum of its proper divisors (1).

120820991 is an equidigital number, since it uses as much as digits as its factorization.

120820991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 120820991 is about 10991.8602156323. The cubic root of 120820991 is about 494.3647137057.

The spelling of 120820991 in words is "one hundred twenty million, eight hundred twenty thousand, nine hundred ninety-one".