42499781 has 4 divisors (see below), whose sum is σ = 43488192. Its totient is φ = 41511372.

The previous prime is 42499777. The next prime is 42499783. The reversal of 42499781 is 18799424.

42499781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 42499781 - 2² = 42499777 is a prime.

It is a super-2 number, since 2×42499781² = 3612462770095922, 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 (42499783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 494141 + ... + 494226.

It is an arithmetic number, because the mean of its divisors is an integer number (10872048).

Almost surely, 2^42499781 is an apocalyptic number.

It is an amenable number.

42499781 is a deficient number, since it is larger than the sum of its proper divisors (988411).

42499781 is an equidigital number, since it uses as much as digits as its factorization.

42499781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 988410.

The product of its digits is 145152, while the sum is 44.

The square root of 42499781 is about 6519.1856086478. The cubic root of 42499781 is about 348.9760029258.

The spelling of 42499781 in words is "forty-two million, four hundred ninety-nine thousand, seven hundred eighty-one".