42390891 has 16 divisors (see below), whose sum is σ = 62955520. Its totient is φ = 28191240.

The previous prime is 42390889. The next prime is 42390917. The reversal of 42390891 is 19809324.

It is not a de Polignac number, because 42390891 - 2¹ = 42390889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42390841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10806 + ... + 14196.

It is an arithmetic number, because the mean of its divisors is an integer number (3934720).

Almost surely, 2^42390891 is an apocalyptic number.

42390891 is a deficient number, since it is larger than the sum of its proper divisors (20564629).

42390891 is a wasteful number, since it uses less digits than its factorization.

42390891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3863 (or 3857 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 42390891 is about 6510.8287490918. The cubic root of 42390891 is about 348.6777072954.

The spelling of 42390891 in words is "forty-two million, three hundred ninety thousand, eight hundred ninety-one".