3991858 has 8 divisors (see below), whose sum is σ = 6448428. Its totient is φ = 1842384.

The previous prime is 3991853. The next prime is 3991877. The reversal of 3991858 is 8581993.

It can be written as a sum of positive squares in 2 ways, for example, as 3674889 + 316969 = 1917^2 + 563^2 .

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

It is not an unprimeable number, because it can be changed into a prime (3991853) 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, 76741 + ... + 76792.

Almost surely, 2^3991858 is an apocalyptic number.

3991858 is a deficient number, since it is larger than the sum of its proper divisors (2456570).

3991858 is a wasteful number, since it uses less digits than its factorization.

3991858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153548.

The product of its digits is 77760, while the sum is 43.

The square root of 3991858 is about 1997.9634631294. The cubic root of 3991858 is about 158.6323268747.

The spelling of 3991858 in words is "three million, nine hundred ninety-one thousand, eight hundred fifty-eight".