40640042 has 4 divisors (see below), whose sum is σ = 60960066. Its totient is φ = 20320020.

The previous prime is 40640009. The next prime is 40640051. The reversal of 40640042 is 24004604.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 29822521 + 10817521 = 5461^2 + 3289^2 .

It is a super-2 number, since 2×40640042² = 3303226027523528, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 40639996 and 40640023.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10160009 + ... + 10160012.

Almost surely, 2^40640042 is an apocalyptic number.

40640042 is a deficient number, since it is larger than the sum of its proper divisors (20320024).

40640042 is a wasteful number, since it uses less digits than its factorization.

40640042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20320023.

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 40640042 is about 6374.9542743458. The cubic root of 40640042 is about 343.8096398118.

Adding to 40640042 its reverse (24004604), we get a palindrome (64644646).

The spelling of 40640042 in words is "forty million, six hundred forty thousand, forty-two".