40645661 has 4 divisors (see below), whose sum is σ = 46452192. Its totient is φ = 34839132.

The previous prime is 40645651. The next prime is 40645663. The reversal of 40645661 is 16654604.

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 a de Polignac number, because none of the positive numbers 2^k-40645661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40645663) 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, 2903255 + ... + 2903268.

It is an arithmetic number, because the mean of its divisors is an integer number (11613048).

Almost surely, 2^40645661 is an apocalyptic number.

It is an amenable number.

40645661 is a deficient number, since it is larger than the sum of its proper divisors (5806531).

40645661 is an equidigital number, since it uses as much as digits as its factorization.

40645661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5806530.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 40645661 is about 6375.3949681569. The cubic root of 40645661 is about 343.8254844258.

The spelling of 40645661 in words is "forty million, six hundred forty-five thousand, six hundred sixty-one".