11991451 has 8 divisors (see below), whose sum is σ = 13030400. Its totient is φ = 10993320.

The previous prime is 11991449. The next prime is 11991457. The reversal of 11991451 is 15419911.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 11991451 - 2¹ = 11991449 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11991457) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9591 + ... + 10768.

It is an arithmetic number, because the mean of its divisors is an integer number (1628800).

Almost surely, 2^11991451 is an apocalyptic number.

11991451 is a deficient number, since it is larger than the sum of its proper divisors (1038949).

11991451 is a wasteful number, since it uses less digits than its factorization.

11991451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20409.

The product of its digits is 1620, while the sum is 31.

The square root of 11991451 is about 3462.8674534264. The cubic root of 11991451 is about 228.8884680278. Note that the first 3 decimals are identical.

The spelling of 11991451 in words is "eleven million, nine hundred ninety-one thousand, four hundred fifty-one".