1408128991 has 4 divisors (see below), whose sum is σ = 1411805952. Its totient is φ = 1404452032.

The previous prime is 1408128983. The next prime is 1408129001. The reversal of 1408128991 is 1998218041.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1408128991 - 2³ = 1408128983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1408128391) 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, 1837906 + ... + 1838671.

It is an arithmetic number, because the mean of its divisors is an integer number (352951488).

Almost surely, 2^1408128991 is an apocalyptic number.

1408128991 is a deficient number, since it is larger than the sum of its proper divisors (3676961).

1408128991 is an equidigital number, since it uses as much as digits as its factorization.

1408128991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3676960.

The product of its (nonzero) digits is 41472, while the sum is 43.

The square root of 1408128991 is about 37525.0448500731. The cubic root of 1408128991 is about 1120.8499582866.

The spelling of 1408128991 in words is "one billion, four hundred eight million, one hundred twenty-eight thousand, nine hundred ninety-one".