9991451 has 2 divisors, whose sum is σ = 9991452. Its totient is φ = 9991450.

The previous prime is 9991441. The next prime is 9991463. The reversal of 9991451 is 1541999.

9991451 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is an emirp because it is prime and its reverse (1541999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9991451 - 2¹⁴ = 9975067 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (9991441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4995725 + 4995726.

It is an arithmetic number, because the mean of its divisors is an integer number (4995726).

Almost surely, 2^9991451 is an apocalyptic number.

9991451 is a deficient number, since it is larger than the sum of its proper divisors (1).

9991451 is an equidigital number, since it uses as much as digits as its factorization.

9991451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14580, while the sum is 38.

The square root of 9991451 is about 3160.9256555636. The cubic root of 9991451 is about 215.3820572924.

The spelling of 9991451 in words is "nine million, nine hundred ninety-one thousand, four hundred fifty-one".