42991819 has 8 divisors (see below), whose sum is σ = 46412352. Its totient is φ = 39587520.

The previous prime is 42991811. The next prime is 42991831. The reversal of 42991819 is 91819924.

It is a happy number.

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 42991819 - 2³ = 42991811 is a prime.

It is a super-2 number, since 2×42991819² = 3696593001857522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42991811) 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, 1767 + ... + 9439.

It is an arithmetic number, because the mean of its divisors is an integer number (5801544).

Almost surely, 2^42991819 is an apocalyptic number.

42991819 is a deficient number, since it is larger than the sum of its proper divisors (3420533).

42991819 is a wasteful number, since it uses less digits than its factorization.

42991819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8117.

The product of its digits is 46656, while the sum is 43.

The square root of 42991819 is about 6556.8146992271. The cubic root of 42991819 is about 350.3175865678.

The spelling of 42991819 in words is "forty-two million, nine hundred ninety-one thousand, eight hundred nineteen".