4007991 has 8 divisors (see below), whose sum is σ = 5755120. Its totient is φ = 2466432.

The previous prime is 4007981. The next prime is 4007999. The reversal of 4007991 is 1997004.

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

It is not a de Polignac number, because 4007991 - 2⁷ = 4007863 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 (4007999) 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, 51346 + ... + 51423.

It is an arithmetic number, because the mean of its divisors is an integer number (719390).

Almost surely, 2^4007991 is an apocalyptic number.

4007991 is a deficient number, since it is larger than the sum of its proper divisors (1747129).

4007991 is a wasteful number, since it uses less digits than its factorization.

4007991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102785.

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

The square root of 4007991 is about 2001.9967532441. The cubic root of 4007991 is about 158.8457425641.

The spelling of 4007991 in words is "four million, seven thousand, nine hundred ninety-one".