42591991 has 8 divisors (see below), whose sum is σ = 46103904. Its totient is φ = 39113760.

The previous prime is 42591971. The next prime is 42592001. The reversal of 42591991 is 19919524.

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

It is a cyclic number.

It is not a de Polignac number, because 42591991 - 2⁵ = 42591959 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 (42591931) 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, 5755 + ... + 10876.

It is an arithmetic number, because the mean of its divisors is an integer number (5762988).

Almost surely, 2^42591991 is an apocalyptic number.

42591991 is a deficient number, since it is larger than the sum of its proper divisors (3511913).

42591991 is a wasteful number, since it uses less digits than its factorization.

42591991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16841.

The product of its digits is 29160, while the sum is 40.

The square root of 42591991 is about 6526.2539791216. The cubic root of 42591991 is about 349.2282068348.

It can be divided in two parts, 425 and 91991, that added together give a square (92416 = 304²).

The spelling of 42591991 in words is "forty-two million, five hundred ninety-one thousand, nine hundred ninety-one".