2021399491 has 2 divisors, whose sum is σ = 2021399492. Its totient is φ = 2021399490.

The previous prime is 2021399461. The next prime is 2021399521. The reversal of 2021399491 is 1949931202.

It is a balanced prime because it is at equal distance from previous prime (2021399461) and next prime (2021399521).

It is a cyclic number.

It is not a de Polignac number, because 2021399491 - 2⁷ = 2021399363 is a prime.

It is not a weakly prime, because it can be changed into another prime (2021399431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1010699745 + 1010699746.

It is an arithmetic number, because the mean of its divisors is an integer number (1010699746).

Almost surely, 2^2021399491 is an apocalyptic number.

2021399491 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021399491 is an equidigital number, since it uses as much as digits as its factorization.

2021399491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 40.

The square root of 2021399491 is about 44959.9765458124. The cubic root of 2021399491 is about 1264.3987291837.

The spelling of 2021399491 in words is "two billion, twenty-one million, three hundred ninety-nine thousand, four hundred ninety-one".