990121247 has 2 divisors, whose sum is σ = 990121248. Its totient is φ = 990121246.

The previous prime is 990121211. The next prime is 990121283. The reversal of 990121247 is 742121099.

It is a balanced prime because it is at equal distance from previous prime (990121211) and next prime (990121283).

It is a cyclic number.

It is not a de Polignac number, because 990121247 - 2¹⁸ = 989859103 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (990121207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495060623 + 495060624.

It is an arithmetic number, because the mean of its divisors is an integer number (495060624).

Almost surely, 2^990121247 is an apocalyptic number.

990121247 is a deficient number, since it is larger than the sum of its proper divisors (1).

990121247 is an equidigital number, since it uses as much as digits as its factorization.

990121247 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 990121247 is about 31466.1921274246. The cubic root of 990121247 is about 996.6961791216.

The spelling of 990121247 in words is "nine hundred ninety million, one hundred twenty-one thousand, two hundred forty-seven".