42651681 has 4 divisors (see below), whose sum is σ = 56868912. Its totient is φ = 28434452.

The previous prime is 42651673. The next prime is 42651703. The reversal of 42651681 is 18615624.

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 42651681 - 2³ = 42651673 is a prime.

It is a super-2 number, since 2×42651681² = 3638331784251522, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (42651641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7108611 + ... + 7108616.

It is an arithmetic number, because the mean of its divisors is an integer number (14217228).

Almost surely, 2^42651681 is an apocalyptic number.

It is an amenable number.

42651681 is a deficient number, since it is larger than the sum of its proper divisors (14217231).

42651681 is a wasteful number, since it uses less digits than its factorization.

42651681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14217230.

The product of its digits is 11520, while the sum is 33.

The square root of 42651681 is about 6530.8254455314. The cubic root of 42651681 is about 349.3912711489.

The spelling of 42651681 in words is "forty-two million, six hundred fifty-one thousand, six hundred eighty-one".