42009781 has 8 divisors (see below), whose sum is σ = 45995328. Its totient is φ = 38052000.

The previous prime is 42009769. The next prime is 42009797. The reversal of 42009781 is 18790024.

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 42009781 - 2²³ = 33621173 is a prime.

It is a super-2 number, since 2×42009781² = 3529643399335922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42009181) 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, 3705 + ... + 9886.

It is an arithmetic number, because the mean of its divisors is an integer number (5749416).

Almost surely, 2^42009781 is an apocalyptic number.

It is an amenable number.

42009781 is a deficient number, since it is larger than the sum of its proper divisors (3985547).

42009781 is a wasteful number, since it uses less digits than its factorization.

42009781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13883.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 42009781 is about 6481.4952750118. The cubic root of 42009781 is about 347.6296457408.

The spelling of 42009781 in words is "forty-two million, nine thousand, seven hundred eighty-one".