407991 has 16 divisors (see below), whose sum is σ = 580608. Its totient is φ = 254400.

The previous prime is 407977. The next prime is 407993. The reversal of 407991 is 199704.

It is not a de Polignac number, because 407991 - 2⁵ = 407959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (407993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3760 + ... + 3866.

It is an arithmetic number, because the mean of its divisors is an integer number (36288).

2⁴⁰⁷⁹⁹¹ is an apocalyptic number.

407991 is a gapful number since it is divisible by the number (41) formed by its first and last digit.

407991 is a deficient number, since it is larger than the sum of its proper divisors (172617).

407991 is a wasteful number, since it uses less digits than its factorization.

407991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182.

The product of its (nonzero) digits is 2268, while the sum is 30.

The square root of 407991 is about 638.7417318447. The cubic root of 407991 is about 74.1680500240.

The spelling of 407991 in words is "four hundred seven thousand, nine hundred ninety-one".