4003994591 has 4 divisors (see below), whose sum is σ = 4142063400. Its totient is φ = 3865925784.

The previous prime is 4003994549. The next prime is 4003994597. The reversal of 4003994591 is 1954993004.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4003994591 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 (4003994597) 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, 69034361 + ... + 69034418.

It is an arithmetic number, because the mean of its divisors is an integer number (1035515850).

Almost surely, 2^4003994591 is an apocalyptic number.

4003994591 is a deficient number, since it is larger than the sum of its proper divisors (138068809).

4003994591 is a wasteful number, since it uses less digits than its factorization.

4003994591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138068808.

The product of its (nonzero) digits is 174960, while the sum is 44.

The square root of 4003994591 is about 63277.1253376763. The cubic root of 4003994591 is about 1587.9292943275.

The spelling of 4003994591 in words is "four billion, three million, nine hundred ninety-four thousand, five hundred ninety-one".