42091021 has 8 divisors (see below), whose sum is σ = 48317760. Its totient is φ = 35917728.

The previous prime is 42091019. The next prime is 42091033. The reversal of 42091021 is 12019024.

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

It is not a de Polignac number, because 42091021 - 2¹ = 42091019 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 42091021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42091321) 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, 11656 + ... + 14833.

It is an arithmetic number, because the mean of its divisors is an integer number (6039720).

Almost surely, 2^42091021 is an apocalyptic number.

It is an amenable number.

42091021 is a deficient number, since it is larger than the sum of its proper divisors (6226739).

42091021 is a wasteful number, since it uses less digits than its factorization.

42091021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26723.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 42091021 is about 6487.7593204434. The cubic root of 42091021 is about 347.8535876143.

The spelling of 42091021 in words is "forty-two million, ninety-one thousand, twenty-one".