42989991 has 16 divisors (see below), whose sum is σ = 66210048. Its totient is φ = 24521600.

The previous prime is 42989987. The next prime is 42989993. The reversal of 42989991 is 19998924.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 42989991 - 2² = 42989987 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42989993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37755 + ... + 38876.

It is an arithmetic number, because the mean of its divisors is an integer number (4138128).

Almost surely, 2^42989991 is an apocalyptic number.

42989991 is a deficient number, since it is larger than the sum of its proper divisors (23220057).

42989991 is a wasteful number, since it uses less digits than its factorization.

42989991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76662.

The product of its digits is 419904, while the sum is 51.

The square root of 42989991 is about 6556.6753007908. The cubic root of 42989991 is about 350.3126213625.

The spelling of 42989991 in words is "forty-two million, nine hundred eighty-nine thousand, nine hundred ninety-one".