40561681 has 4 divisors (see below), whose sum is σ = 41075200. Its totient is φ = 40048164.

The previous prime is 40561679. The next prime is 40561699. The reversal of 40561681 is 18616504.

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 40561681 - 2¹ = 40561679 is a prime.

It is a super-2 number, since 2×40561681² = 3290499931091522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40561601) 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, 256641 + ... + 256798.

It is an arithmetic number, because the mean of its divisors is an integer number (10268800).

Almost surely, 2^40561681 is an apocalyptic number.

It is an amenable number.

40561681 is a deficient number, since it is larger than the sum of its proper divisors (513519).

40561681 is an equidigital number, since it uses as much as digits as its factorization.

40561681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513518.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 40561681 is about 6368.8053039797. The cubic root of 40561681 is about 343.5885229016.

The spelling of 40561681 in words is "forty million, five hundred sixty-one thousand, six hundred eighty-one".