991335451 has 4 divisors (see below), whose sum is σ = 991400904. Its totient is φ = 991270000.

The previous prime is 991335407. The next prime is 991335463. The reversal of 991335451 is 154533199.

991335451 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 154533199 = 29 ⋅5328731.

It is a 4-Lehmer number, since φ(991335451) divides (991335451-1)⁴.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991335451 is a prime.

It is a deceptive number, since it divides R_991335450.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991335481) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2976 + ... + 44626.

It is an arithmetic number, because the mean of its divisors is an integer number (247850226).

Almost surely, 2^991335451 is an apocalyptic number.

991335451 is a deficient number, since it is larger than the sum of its proper divisors (65453).

991335451 is a wasteful number, since it uses less digits than its factorization.

991335451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65452.

The product of its digits is 72900, while the sum is 40.

The square root of 991335451 is about 31485.4800026933. The cubic root of 991335451 is about 997.1034350121.

The spelling of 991335451 in words is "nine hundred ninety-one million, three hundred thirty-five thousand, four hundred fifty-one".