42645991 has 4 divisors (see below), whose sum is σ = 42710032. Its totient is φ = 42581952.

The previous prime is 42645989. The next prime is 42646001. The reversal of 42645991 is 19954624.

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

It is a cyclic number.

It is not a de Polignac number, because 42645991 - 2¹ = 42645989 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 (42645931) 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, 31011 + ... + 32356.

It is an arithmetic number, because the mean of its divisors is an integer number (10677508).

Almost surely, 2^42645991 is an apocalyptic number.

42645991 is a deficient number, since it is larger than the sum of its proper divisors (64041).

42645991 is an equidigital number, since it uses as much as digits as its factorization.

42645991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64040.

The product of its digits is 77760, while the sum is 40.

The square root of 42645991 is about 6530.3898045982. The cubic root of 42645991 is about 349.3757334671.

The spelling of 42645991 in words is "forty-two million, six hundred forty-five thousand, nine hundred ninety-one".