42639993 has 16 divisors (see below), whose sum is σ = 68913600. Its totient is φ = 25842240.

The previous prime is 42639991. The next prime is 42640001. The reversal of 42639993 is 39993624.

42639993 is a `hidden beast` number, since 4 + 2 + 639 + 9 + 9 + 3 = 666.

It is not a de Polignac number, because 42639993 - 2¹ = 42639991 is a prime.

It is not an unprimeable number, because it can be changed into a prime (42639991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71488 + ... + 72081.

It is an arithmetic number, because the mean of its divisors is an integer number (4307100).

Almost surely, 2^42639993 is an apocalyptic number.

It is an amenable number.

42639993 is a deficient number, since it is larger than the sum of its proper divisors (26273607).

42639993 is a wasteful number, since it uses less digits than its factorization.

42639993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143589 (or 143583 counting only the distinct ones).

The product of its digits is 314928, while the sum is 45.

The square root of 42639993 is about 6529.9305509324. The cubic root of 42639993 is about 349.3593532333.

The spelling of 42639993 in words is "forty-two million, six hundred thirty-nine thousand, nine hundred ninety-three".