9921491 has 2 divisors, whose sum is σ = 9921492. Its totient is φ = 9921490.

The previous prime is 9921479. The next prime is 9921521. The reversal of 9921491 is 1941299.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9921491 - 2¹⁰ = 9920467 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (9921391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4960745 + 4960746.

It is an arithmetic number, because the mean of its divisors is an integer number (4960746).

Almost surely, 2^9921491 is an apocalyptic number.

9921491 is a deficient number, since it is larger than the sum of its proper divisors (1).

9921491 is an equidigital number, since it uses as much as digits as its factorization.

9921491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 35.

The square root of 9921491 is about 3149.8398371981. The cubic root of 9921491 is about 214.8781786892.

The spelling of 9921491 in words is "nine million, nine hundred twenty-one thousand, four hundred ninety-one".